Bowel Perforation in Covid-19 Case Series

OBJECTIVE

To describe the clinical characteristics and outcomes of patients with coronavirus disease 2019(COVID-19) who developed bowel perforation.

MATERIALS AND METHODS

This case series was conducted in Emergency Department of AORN Sant'Anna and S. Sebastiano located in Caserta. All patients resulted positive to SARS-Cov-2 in nasopharyngeal swabs whith a positive laboratory test for SARS-CoV-2 from real time reverse transcription polymerase chain reaction(RT-PCR) as well as bowel perforation which was identified by abdominal CT, from September 2020 to December 2020.

RESULTS

A total of five patients were identified with Bowel perforation occurred despite all patients being on anticoagulation. All patients were Italian, predominantly male(four patients) with an average age of 60 years and the most common comorbidity was hypertension, diabetes and obesity.

DISCUSSION

Bowel perforation in COVID-19 is clinically significant with high morbidity and mortality. In our series 40% of patients who were diagnosed of bowel perforation died. Average time to death after bowel perforation diagnosis was 6 days.

CONCLUSION

We describe a case series of COVID-19 patients who developed bowel perforation.

KEY WORDS

Covid-19, Bowel perforation.

Dynamical model for sympatric speciation in an ecological niche

The speciation phenomenon is the process used by the evolution to allow populations to become distinct species. The speciation is the primary cause of the complexity of the ecological network. Sympatric speciation concerns the rise of a new species from a surviving ancestral species while both continue to inhabit the same ecological niche or geographical region. In sympatric speciation, reproductive isolation evolves within a population in an ecological niche without the aid of geographic barriers. Different models have been proposed for alternative modes of sympatric speciation. The most popular was first put forward by John Maynard Smith in 1966 who suggested that in a given population homozygous individuals may, under particular environmental conditions, have a greater fitness than those with alleles heterozygous for a certain trait, eventually leading to speciation in the population. In this framework we assume an effective description of the speciation process based on a dynamical model for the populations in an ecological system. Our basic assumption is the existence of an ancestral population in an ecological niche that can express two phenotypes. In presence of certain environmental conditions one of the phenotypes has the propensity to separate from the original population in the reproduction process. Then new individuals may give rise to a new species in the ecosystem realizing a sympatric speciation. Due to the finite resources in the niche the populations are continuously competing each other's, and their numerousness fluctuates according to the changes of the environmental conditions. The effect of natural selection is introduced in the model by stochastic perturbations, that decrease the reproduction rate of the populations in the niche. We show some the dynamical properties of the system and we prove the existence of a threshold values in the environmental stress in order to observe the speciation process. We also discuss some biological implications of the model and the validation problem using empirical data.

Effect of hepatitis B virus on steatosis in hepatitis C virus co-infected subjects: A multi-centre study and systematic review

It remains unclear whether hepatitis B virus (HBV) infection may modify the severity of viral steatosis in patients coinfected with chronic hepatitis C virus (HCV). We examined the influence of coinfection with HBV on prevalence of steatosis in chronic hepatitis C in a multi-centre cohort of HBV-HCV subjects, and by performing a systematic review and meta-analysis of the literature. We centrally and blindly assessed steatosis prevalence and severity in a cohort of HBV-HCV coinfected subjects compared to HCV and HBV monoinfected controls and we performed a systematic review of studies addressing the prevalence of steatosis in HBV-HCV subjects compared to HCV controls. In the clinical cohort, we included 85 HBV-HCV, 69 HBV and 112 HCV subjects from 16 international centres. There was no significant difference in steatosis prevalence between the HBV-HCV and the HCV groups (33% vs 45%, P = .11). In subgroup analysis, lean HBV-HCV subjects with detectable HBV DNA had less steatosis than lean HCV subjects matched for HCV viremia (15% vs 45%, P = .02). Our literature search identified 5 additional studies included in a systematic review. Overall, prevalence of steatosis > 5% was similar in HBV-HCV infection compared to HCV (pooled odds ratio [OR] 0.91, 95% CI 0.53-1.6) although there was significant heterogeneity (I² 69%, P = .007). In conclusion, although the prevalence of steatosis is similar in HBV-HCV compared to HCV subjects, our analysis suggests that there may be an inhibitory effect of HCV-induced steatogenesis by HBV in certain subgroups of patients.

Numerical solution of a diffusion problem by exponentially fitted finite difference methods

This paper is focused on the accurate and efficient solution of partial differential differential equations modelling a diffusion problem by means of exponentially fitted finite difference numerical methods. After constructing and analysing special purpose finite differences for the approximation of second order partial derivatives, we employed them in the numerical solution of a diffusion equation with mixed boundary conditions. Numerical experiments reveal that a special purpose integration, both in space and in time, is more accurate and efficient than that gained by employing a general purpose solver.

Inosine triphosphatase deficiency helps predict anaemia, anaemia management and response in chronic hepatitis C therapy

Anaemia frequently complicates peginterferon/ribavirin therapy for chronic hepatitis C infection. Better prediction of anaemia, ribavirin dose reduction or erythropoietin (EPO) need, may enhance patient management. Inosine triphosphatase (ITPA) genetic variants are associated with ribavirin-induced anaemia and dose reduction; however, their impact in real-life clinic patient cohorts remains to be defined. We studied 193 clinic patients with chronic hepatitis C infection of mixed viral genotype (genotype 1/4 n = 123, genotype 2/3, n = 70) treated with peginterferon/ribavirin. Patients were genotyped for ITPA polymorphisms rs1127354 and rs7270101 using Taqman primers. Hardy-Weinberg equilibrium was present. Estimated ITPA deficiency was graded on severity (0-3, no deficiency/mild/moderate/severe, n = 126/40/24/3, respectively). Multivariable models tested the association with anaemia at 4 weeks of treatment [including decline in haemoglobin (g/dL); haemoglobin <10 g/dL and haemoglobin decline >3 g/dL]; ribavirin dose reduction and EPO use and explored sustained viral response (SVR) to peginterferon/ribavirin. More severe ITPA deficiency was associated with less reduction in haemoglobin level (P <0.001; R(2) = 0.34), less ribavirin dose reduction (OR 0.42; (95% CI = 0.23-0.77); P = 0.005) and less EPO use [OR 0.53; (0.30-0.94); P = 0.029]. ITPA deficiency was associated with SVR [OR: 1.70; (1.02-2.83); P = 0.041] independently of clinical covariates (adjusted R(2) = 0.31). In this clinical cohort, ITPA deficiency helped predict the risk of on-treatment anaemia, ribavirin dose reduction, need for EPO support and was associated with SVR. For patients on HCV regimens including peginterferon/ribavirin, testing for ITPA deficiency may have clinical utility.

Levels and congener profiles of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and dioxin-like polychlorinated biphenyls in cow's milk collected in Campania, Italy

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and certain dioxin-like polychlorinated biphenyls (dl-PCBs) are a family of chemically-related lipophilic compounds characterized by similar toxicity. Due to their properties they are universally distributed in the environment and classified as persistent organic pollutants (POPs). From most of studies carried out to evaluate human dietary intake, milk and dairy products result as a major contributors of PCDD/Fs uptake. Of course the main source of milk contamination is animal feeds. Lactating ruminants, cows included, transfer these compounds to the food chain by ingestion of contaminated vegetables or soil. Their resistance to degradation and a high lipophilicity means that PCDD/Fs and dl-PCBs may be accumulated into fat tissues from which they are transferred to milk during lactation period. Seventy-nine cows milk samples, collected in the monitoring plan 2008, were analyzed for PCDD/Fs and dl-PCBs. Eleven milk samples were non-compliant corresponding to five breeding livestock located in Caserta province. The distribution of PCDD/Fs and dl-PCBs congeners in these samples was examined in order to determine the likely sources of dioxins. The results show that the congener profile is characterized by a prevalence of PCDFs in respect of PCDDs, that represents the typical pattern of thermal origin contamination.

[Treatment of splenic trauma in paediatric age]

The splenic trauma in children presents some peculiarity that differentiates it from that one in adult age. Therefore we have see again our relative experience on splenic trauma, in the period 2001-2006, confronting two groups of patients, one of inferior age to fourteen years (A Group) and one of advanced age (B Group). We have estimated the following parameters: aetiology, type of lesion, association with others trauma, type of treatment, compliance, mortality, number of transfusions and hospital stay. On a total of 75 splenic trauma (M:52, F:23 of age comprised between 5 and 71 years) 18 belongs to the A group (medium age of 9.2 years) and 57 to the B group (medium ages of 47.4 years). The prevailing aetiology in the A group is domestic accident (39%) and the fall from bicycle (33%), while in the B group it is the street accident (69%). The lesions found in pediatric age are of smaller gravity if compared with B group, for lesion gravity and for association with abdominal and/or extra-abdominal others trauma. In the children group we have performed nonoperative management or conservative surgery in the 83% of cases versus the 26% in the B group. The rate of conversion from a nonoperative treatment in to an operative treatment has been of 7%. The post-operative complicance are absent in the A group and of 5.5% in the B group. The mortality rate in the surgical patients has been of the 14.3% for serious toraco-abdominal trauma in A group and of 11.1% in B group. No mortality is detected in the groups with nonoperative treatment. The medium number of transfusions is of 1.8 units in the paediatric patients and of 2.5 units in the adults. The medium stay in hospital is of eighteen days in the A group and of thirteen days in the B group. In conclusion the marked difference in the two groups examines stays in the type of treatment, more often nonoperative or conservative in the children group.

[Hepatic haemorrhage in pregnancy: a case report]

Spontaneous hepatic haemorrhage in pregnancy (SHHP) is a rare event (1 woman out of 15,000). It is generally considered as an advanced state of the microangiopathic hemolytic anemia (HELLP, Hemolysis, Elevated Liver enzyme levels, Low Platelet count). Furthermore, the HELLP is considered as a different form of preeclampsia. The patient, a 33-year-old-woman at 30 weeks' gestation, was admitted to hospital for preeclampsia, underwent an emergency Stark caesarean section with the extraction of an alive foetus and evidence of massive intraperitonal haemorrhage from a large hepatic haematoma. A haemostasis with gauzes of Surgicel was performed, with consequent arrest of the haemorrhage. After approximately 6 hours, a recurrence of the intraperitonal haemorrhage led to a new surgical intervention with hepatic packing with gauzes. After 4 days the patient died. The etiopathogenesis of disease is uncertain, both foetal and maternal mortality are high, and the slight number of reported cases (27) of SPPH from HELLP in international literature offer elements for debate. The following points have been put forward: 1. the monitoring of the counts of the platelets represent the only valid predictive test of HELLP. These concerned women in the third trimester of pregnancy, especially those with a history of preeclampsia; 2. the treatment must be immediate, intensive and multidisciplinary, the plasmapheresis has remarkably improved the prognosis; 3. surgical treatment performed in order to control the SPPH makes use of packing, embolization and/or fastening of the common hepatic artery and, in extreme cases, total hepatectomy with transplantation. The Authors believe it is useful to suggest a national epidemiological research in order to estimate the real incidence of the syndrome in Italy and to establish the guidelines for the medico-surgical treatment.

[The meshes of polypropylene in emergency surgery for strangulated hernias and incisional hernias]

INTRODUCTION

The Authors present their experience on the use of meshes of polypropylene in septic surgery of the abdominal wall defects.

MATERIALS AND METHODS

From April 1999 to October 2003, 23 patients underwent intestinal resection (20 small intestine, 3 large intestine) for ischemic necrosis strangulation caused by defects in the abdominal wall (inguinal hernia 8, crural hernia 4, umbilical hernia 3, post-incisional hernia under umbilicus 3, post-incisional hernia epigastric 3, giant post-incisional hernia 2).

RESULTS

No patient died and the removal of the mesh was never required in cases of infection of the surgical wound; 2 surgical wounds festered, with the reopening of the cutaneous wound and showing of the prosthesis, 5 hygromas were all treated in a conservative way.

DISCUSSION

The macroporous structure of the meshes of polypropylene, with pores of diameter larger than 70 microns, allows contact among the bacteria, which measure one micron in diameter, and the cells of the immune system, granulocytes and macrophages, with a diameter of 15-20 microns, allowing the recovery from infections, and determining an high resistance rate to infections.

CONCLUSIONS

Polypropylene prostheses, thanks to their macroporous structure, are sufficiently resistant to infections and therefore may be safely used in the surgery of the defects of the abdominal wall, when, following ischemic necrosis, an intestinal resection is necessary.

[Emergency surgery for neoplastic left colon obstruction: resection and primary anastomosis (RPA) versus Hartmann resection (HR)]

This retrospective study compares: hospitalization time, morbidity and mortality (patients operated for neoplastic occlusion of the left colon in emergency, without perforation), considering hanestesiologic risk and surgical technique (RPA versus RH).

MATERIALS AND METHODS

From April 1999 to February 2003 the Emergency Surgery of AORN of Caserta has operated, in urgency, 60 neoplastic patients with left colon occlusion realizing: 46 (76.5%) RPA [36 ASA < or = III, low hanestesiologic risk (LAR), 10 ASA = or > IV high hanestesiologic risk (HAR)], 12 (20%) RH (2 LAR and 10 HAR) 2 (3.5%) palliative colostomics.

RESULTS

36 LAR patients with RPA had 5% of specific complications and 5% of medical complications. 2 LAR patients with R-H: no complication. 10 HAR patient with RPA brought 10% of specific complications and 10% of medical complications. 10 HAR patients with RH had 20% of specific complications and 10% of general complications. The middle hospitalization of LAR patients with RPA was 11 days versus 9 days of RH pz. (equal hanestesiologic risk ). The HAR pz., treated with RPA, had as middle hospitalization 15 ggs in comparison to the 9 ggs of the HRA pz. treated with RH.

MORTALITY

1/36 for LAR pz. with RPA (3%), and 0/0 for LAR pz. with RH; 1/10 for HAR pz, with RPA (10%) and 1/10 for HAR pz. with RH (10%).

CONCLUSIONS

Resection and primary anastomosis, (correct indications and expert surgeon), gives prevalence of complications and mortality similar to the repeated surgical procedure, a better life quality, but an higher number of post-operating hospitalisation days.

Increased vascular endothelial growth factor mRNA expression in the heart of streptozotocin-induced diabetic rats

The aim of the present study was to evaluate vascular endothelial growth factor (VEGF), fms-like tyrosine kinase 1 (flt-1), and fetal liver kinase (flk-1) expression in the heart of experimental diabetic rats. Ten young adult male Wistar rats (5 streptozotocin [STZ]-induced diabetic rats, without insulin treatment, and 5 controls) were studied. Ninety days after the induction of diabetes, semiquantitative reverse transcription (RT)-polymerase chain reaction (PCR) coamplification of VEGF/glyceraldehyde 3-phosphate dehydrogenase (GAPDH) transcription was performed. RT-PCR was also performed for VEGF receptors flk-1 and flt-1. VEGF mRNA expression, at 234 bp, was detectable in the heart of the rats and was significantly higher in those with diabetes. Densitometric analysis of PCR products showed that VEGF mRNA levels were meanly 4.8-fold higher in STZ-induced diabetic rats than controls (VEGF/GAPDH densitometric ratio, 3.46 +/- 0.20 v 0.74 +/- 0.10, P <.001). No significant difference was found in flt-1 and flk-1 amplification products between STZ-induced diabetic rats and controls (flt-1/GAPDH densitometric ratio, 0.58 +/- 0.01 v 0.64 +/- 0.05, P>.1; flk-1/GAPDH densitometric ratio, 0.66 +/- 0.10 v 0.7 +/- 0.06, P >.2). The increase in VEGF mRNA expression observed in this experimental diabetic model is in contrast with the typical impairment in collateral vessels of diabetic hearts. This apparent discrepancy might be explained by a resistance of cardiac tissue to VEGF. The lack of mRNA flt-1 and flk-1 overexpression in diabetic hearts could be one of the mechanisms for this resistance.

[Intraperitoneal hemorrhage from rupture of an aneurysm of splenic artery: case report and literature review]

Splenic artery aneurysm presented with rupture is an unusual and potentially deadly reason of intraperitoneal hemorrhage. There are a lot of pathogenetic hypothesis; timing according to disease severity and surgical choices aren't definitely codified authors present one patient with hemoperitoneum for ruptured splenic artery aneurysm affected by chronic lymphatic leukaemia too and review international literature; they underline pathogenesis, symptoms, preoperative investigations and therapy. Degeneration of the media, atherosclerotic changes and high blood flow due to pregnancy and portal hypertension could be the main pathogenetic factors. Ultrasonography is the first investigation we have to practice if we suspect hemoperitoneum. We can practice computed tomography and angiography too if cardiovascular condition are good. Rupture showing acute abdominal pain and cardiovascular collapse suggest strongly urgent operation. The choice of operation is determined by location of the aneurysm. When located in the distal third of the splenic artery, the aneurysm is resected with spleen; alternatively, when it is located in prossimal third we can perform conservative operation.

[Pica: a clinical case and therapeutic problems]

Pica is a psychotic disorder characterized by compulsive ingestion of nonfood substances; the primary treatment is the prevention with antipsychotic therapy. When the patient ingests foreign body, endoscopical removal is recommended. Surgical treatment is necessary when an acute abdomen is present, with intestinal occlusion and/or bowel perforation. The Authors report a peculiar case of pica, and analyse the problems of organization and assistance, besides surgical approach, also on the base of international literature.

[Peutz-Jeghers syndrome: case report and update on diagnosis and treatment]

Peutz-Jeghers syndrome is a rare autosomal dominantly inherited condition with an incidence of 1/120.000 liveborns, characterized by the presence of hamartomatous gastrointestinal polyps and mucocutaneous pigmentation. This syndrome predisposes to various clinical problems such as intussusception and cancer development in different loci (gastrointestinal tract, breast and ovary). For this reason, PJS patients should undergo a surveillance protocol of the genital and gastrointestinal apparatus. Therefore, the early diagnosis of PJS in at-risk family members is very important in preventing cancer development. Germline mutations within the LKB1 or Serine Threonine Kinase (STK11) gene, located on chromosome 19p13.3, are responsible for most cases of PJS so far studied. The existence of a second locus is suspected on chromosome 19q13.4 in a minority of families. The LKB1 gene, recently cloned, encodes the Serine Threonine Kinase LKB1 and is ubiquitously expressed. The identification of the disease-causing mutation in each family makes it possible to perform a presymptomatic diagnosis; therefore, only the mutation carriers will undergo the clinical surveillance program. In this paper, the case of a PJS patient who has been surgically treated is presented. The DNA screening of the LKB1 gene in this patient has led to the identification of the causing mutation. A critical review of the literature and is also presented as well as the proposal to establish an Italian Registry of PJS.

Impaired K(+) homeostasis and altered electrophysiological properties of post-traumatic hippocampal glia

Traumatic brain injury (TBI) can be associated with memory impairment, cognitive deficits, or seizures, all of which can reflect altered hippocampal function. Whereas previous studies have focused on the involvement of neuronal loss in post-traumatic hippocampus, there has been relatively little understanding of changes in ionic homeostasis, failure of which can result in neuronal hyperexcitability and abnormal synchronization. Because glia play a crucial role in the homeostasis of the brain microenvironment, we investigated the effects of TBI on rat hippocampal glia. Using a fluid percussion injury (FPI) model and patch-clamp recordings from hippocampal slices, we have found impaired glial physiology 2 d after FPI. Electrophysiologically, we observed reduction in transient outward and inward K(+) currents. To assess the functional consequences of these glial changes, field potentials and extracellular K(+) activity were recorded in area CA3 during antidromic stimulation. An abnormal extracellular K(+) accumulation was observed in the post-traumatic hippocampal slices, accompanied by the appearance of CA3 afterdischarges. After pharmacological blockade of excitatory synapses and of K(+) inward currents, uninjured slices showed the same altered K(+) accumulation in the absence of abnormal neuronal activity. We suggest that TBI causes loss of K(+) conductance in hippocampal glia that results in the failure of glial K(+) homeostasis, which in turn promotes abnormal neuronal function. These findings provide a new potential mechanistic link between traumatic brain injury and subsequent development of disorders such as memory loss, cognitive decline, seizures, and epilepsy.

Frequency-dependent changes in cerebral blood flow and evoked potentials during somatosensory stimulation in the rat

Contrary to the concept of neuronal-vascular coupling, cortical evoked potentials do not always correlate with blood flow responses during somatosensory stimulation at changing stimulus rates. The goal of this study is to clarify the effects of stimulus frequency on the relationship between somatosensory evoked potentials (SEPs) and cerebral blood flow. In rats anesthetized with alpha-chloralose, we measured SEPs by signal-averaging field potentials recorded with an electrode placed on dura overlying the hindlimb somatosensory cortex. Regional blood flow was simultaneously assessed in the same region with a laser-Doppler flow (LDF) probe. The contralateral sciatic nerve was stimulated with 0.1 A pulses at the frequencies of 1, 2, 5, 10 and 20 Hz. SEPs (both P1 and N1 components) declined with increasing frequency regardless whether stimulus duration (20 s) or number (100) were kept constant, suggesting that frequency is an important determinant of neuronal activity. In contrast, LDF responses increased to a maximum at 5 Hz, and do not correlate with SEPs. Because CBF should reflect integrated neuronal activity, we computed the sum of SEPS (summation operatorSEP = SEP x stimulus frequency) as an index of total neuronal activity at each frequency. Summation operatorSEP indeed correlates positively (P<0.001) with LDF responses. Thus, during somatosensory stimulation at various frequencies, cerebral blood flow is coupled to integrated neuronal activity but not to averaged evoked potentials.

Extracellular chloride and the maintenance of spontaneous epileptiform activity in rat hippocampal slices

Previous studies showed that furosemide blocks spontaneous epileptiform activity without diminishing synaptic transmission or reducing hyperexcited field responses to electrical stimuli. We now test the hypothesis that the antiepileptic effects of furosemide are mediated through its blockade of the Na+,K+,2Cl- cotransporter and thus should be mimicked by a reduction of extracellular chloride ([Cl-]o). In the first set of experiments, field recordings from the CA1 cell body layer of hippocampal slices showed that spontaneous bursting developed within 10-20 min in slices perfused with low-[Cl-]o (7 mM) medium but that this spontaneous epileptiform activity ceased after a further 10-20 min. Intracellular recordings from CA1 pyramidal cells showed that normal action potential discharge could be elicited by membrane depolarization, even after the tissue was perfused with low-[Cl-]o medium for >2 h. In a second set of experiments, spontaneous bursting activity was induced in slices by perfusion with high-[K+]o (10 mM), bicuculline (100 microM), or 4-aminopyridine (100 microM). In each case, recordings from the CA1 region showed that reduction of [Cl-]o to 21 mM reversibly blocked the bursting within 1 h. Similar to previous observations with furosemide treatment, low-[Cl-]o medium blocked spontaneous hypersynchronous discharges without reducing synaptic hyperexcitability (i.e., hyperexcitable field responses evoked by electrical stimulation). In a third set of experiments, prolonged exposure (>1 h after spontaneous bursting ceased) of slices to systematically varied [Cl-]o and [K+]o resulted in one of three types of events: 1) spontaneous, long-lasting, and repetitive negative field potential shifts (7 mM [Cl-]o; 3 mM [K+]o); 2) oscillations consisting of 5- to 10-mV negative shifts in the field potential, with a period of approximately 1 cycle/40 s (16 mM [Cl-]o; 12 mM [K+]o); and 3) shorter, infrequently occurring negative field shifts lasting 20-40 s (21 mM [Cl-]o; 3 mM [K+]o). Our observations indicate that the effects of low [Cl-]o on neuronal synchronization and spontaneous discharge are time dependent. Similar effects were seen with furosemide and low [Cl-]o, consistent with the hypothesis that the antiepileptic effect of furosemide is mediated by the drug's effect on chloride transporters. Finally, the results of altering extracellular potassium along with chloride suggest that blockade of the Na+, K+,2Cl- cotransporter, which normally transports chloride from the extracellular space into glial cells, is key to these antiepileptic effects.

Functional specialization and topographic segregation of hippocampal astrocytes

Astrocytes have been suggested to play several roles in the complex control of brain microenvironment. However, they have been generally considered to constitute a homogeneous population of cells. Here we show that at least three electrophysiologically distinct types of astrocytes can be found in the mature hippocampus. These subpopulations of glia were characterized by expression of different ion currents. In astrocytes exposed to elevated K+, Cs+ prevented influx of K+ only in cells with inwardly rectifying currents (IIR). The topographic distribution of glia with Cs+-sensitive inward rectifying currents (involved in K+ buffering) was nonuniform. Cs+-sensitive astrocytes were predominantly found in CA3 radiatum, whereas most CA1 astrocytes were Cs+-insensitive. Functional significance of the spatial segregation of glial cells with inward rectification was addressed in slices that were bathed in Cs+-containing media. Under these conditions, neuronal stimulation induced spontaneous epileptiform activity, which first appeared in CA3 and was then synaptically propagated to CA1. Intracellular labeling of astrocytes with biocytin revealed that CA1 astrocytes are characterized by a high degree of cell-to-cell coupling; in contrast, cell labeling in CA3 revealed smaller groups and occasionally individual cells. Three individual biocytin-labeled cells had electrophysiological properties indistinguishable from Cs+-sensitive astrocytes but had morphology typical of oligodendroglia. These results provide evidence for a role of K+ uptake via IIR into astrocytes. The segregated expression of potassium channels in a subpopulation of astrocytes suggests that functionally specialized cell types are involved in K+ homeostasis.

Selective loss of hippocampal long-term potentiation, but not depression, following fluid percussion injury

We investigated the early effects of in vivo fluid percussion injury (FPI) on hippocampal synaptic potentials and excitability. In vitro field potential recordings and immunocytochemistry were performed in the CA1 region in slices from naïve, post-FPI, or sham-operated rats. The following electrophysiological and morphological parameters were affected following FPI: (1) threshold for population spike generation was increased suggesting that post-FPI neurons were hypoexcitable; (2) long-term potentiation (LTP) could not be induced in injured hippocampi; (3) GFAP and inducible NO synthase (iNOS) immunoreactivity were enhanced post-FPI; and (4) following injury, synaptophysin immunoreactivity was enhanced in CA1 stratum radiatum. The effects of FPI on synaptic plasticity were LTP-specific, since long-term depression (LTD) could be equally induced and maintained in post-FPI, sham-operated and control slices. Sham-operated slices were characterized by synaptic excitability indistinguishable from naïve controls, but displayed decreased ability for LTP production and expressed high levels of iNOS. We conclude that FPI causes a selective loss of LTP, possibly due to a previous potentiation induced by trauma as reflected by the increased expression of synaptic proteins. Sham surgical procedures were, however, not without effects on long-term potentiation itself; the latter effects appear to be mediated by an increased production of NO. Our study demonstrates for the first time that hippocampal slices can be used to investigate the correlates of in vivo FPI. Furthermore, we describe LTP-specific deficits in post-traumatic brain injury, suggesting that FPI can selectively erase one of the two main NMDA-dependent forms of synaptic plasticity in the hippocampus.

Heterogeneity of astrocyte resting membrane potentials and intercellular coupling revealed by whole-cell and gramicidin-perforated patch recordings from cultured neocortical and hippocampal slice astrocytes

Astrocytes are thought to regulate the extracellular potassium concentration by mechanisms involving both voltage-dependent and transport-mediated ion fluxes combined with intercellular communication via gap junctions. Mechanisms regulating resting membrane potential (RMP) play a fundamental role in determining glial contribution to buffering of extracellular potassium and uptake of potentially toxic neurotransmitters. We have investigated the passive electrophysiological properties of cultured neocortical astrocytes and astrocytes recorded in hippocampal slices from 18-25 d postnatal rats. These experiments revealed a wide range of astrocyte RMPs that were independent of developmental factors, length of culturing, cellular morphology, the electrophysiological techniques used (whole-cell vs perforated recording), cell-specific expression of Na+/2HCO3- co-transporters, or voltage-dependent Na+ channels. Exposure of cultured astrocytes to differentiation-inducing factors (such as cAMP) or inhibition of proliferation (by serum deprivation) did not significantly influence RMP. Expression of ATP-sensitive potassium channels was absent in these glia; thus, K(ATP)-related mechanisms did not contribute to cell resting potential. In both cultured and slice astrocytes, spontaneous electrophysiological changes were commonly observed. These reversible events, which resulted in differential sensitivity to potassium channel blockers (cesium and barium) and sudden current-voltage profile changes, were attributable to dynamic changes in cell-to-cell coupling, as confirmed by recordings from isolated pairs of cells. We conclude that the heterogeneity of astrocytic RMP and intercellular coupling both in culture and in situ are intrinsic properties of glia that may contribute to transcellular transport of potassium. We propose a model in which spatial buffering may be facilitated by heterogeneous mechanisms controlling glial RMP in combination with dynamic changes in intercellular coupling.

Reduction of K+ uptake in glia prevents long-term depression maintenance and causes epileptiform activity

Extracellular cesium causes synchronous, interictal-like bursting and prevents maintenance of long-term depression (LTD) in the CA1 hippocampal region. We have investigated the cellular mechanisms underlying cesium actions. Whole-cell recordings showed that brief (2 min) bath exposures to cesium caused pyramidal cell hyperpolarization associated with decreased membrane conductance attributable to blockade of an inward h-type current. After prolonged (>2 min) exposures, a late depolarizing response was observed; this effect was not associated with changes in cell membrane conductance. Recordings from interneurons revealed that Ih is expressed in a subpopulation of cells and that cesium effects on interneurons expressing Ih are comparable to those observed in pyramidal cells. Consistent with this effect, cesium decreased the early component of the IPSP recorded in pyramidal cells. Interneurons lacking Ih were not affected by cesium but developed a depolarizing response when drug applications were paired to orthodromic stimulation. We concluded that cesium actions on LTD and cesium-induced epileptiform activity were not attributable exclusively to its direct effects on neurons. Recordings from hippocampal slice astrocytes revealed that cesium interfered with glial electrical responses during LTD induction. Cesium blocked glial inwardly rectifying potassium channels and increased the amplitude and duration of stimulation-evoked [K+]out increases. Thus, the effects of cesium on CA1 synchronization and synaptic plasticity appear to be mediated predominantly by blockade of glial voltage-dependent potassium uptake.

Radioimmunoassay of zidovudine: extended use and potential application

When first approved, the dosing regimens for zidovudine were 1,200-1,500 mg/day; however, because toxicity developed, the daily dose had to be reduced to 500-600 mg/day. At these lower doses, plasma concentrations for a considerable segment of the dosing interval are often below the assay sensitivity for the high-performance liquid chromatography (HPLC) method. Although commonly used, the zidovudine radioimmunoassay has had minimal documentation for the quantitative analysis of clinical samples, especially at current doses. The authors' findings indicate that plasma, urine treated with phosphate buffer, and cerebrospinal fluid samples may be assayed using a commercially available radioimmunoassay. A good correlation was found for clinical samples measured by radioimmunoassay and HPLC (R2 = 0.85). The greater assay sensitivity, ability to process multiple specimens, and the relatively rapid turnaround time suggest that the zidovudine radioimmunoassay may have an important role in clinical trials evaluating zidovudine pharmacokinetics. This report summarizes the authors' experience with the zidovudine radioimmunoassay and focuses on its potential use in studying the role of therapeutic drug monitoring for zidovudine.

[The washout in emergency surgery of the colon. A technical note]

The authors report their experience in the treatment of 179 cases of colonic neoplasm between January 1985 and August 1992. Particularly, they emphasize the advantages of one-stage colectomy with anastomosis because of an obstructing carcinoma of the left colon, used on 41 cases. This treatment can be practicable by using the intraoperative "wash-out" technique. The one-stage colectomy with anastomosis can be advisable because the long survival can be compared to that deriving from the non obstructing carcinoma. Moreover this technique offers several advantages such as the one-stage treatment, the absence of colostomy, the improvement of the cost-benefit relationship, etc. On 41 cases treated by this technique, the authors lament only one decease caused by a total dehiscence of the anastomosis, notwithstanding reintervention. Moreover, 9 cases of partial dehiscence were treated by NPT (Total Parenteral Nutrition) except one which demanded a reintervention.

[Acute appendicitis in pregnancy. Our experience]

The authors' aim is to review the medical literature dealing with diagnostic and therapeutical problems, after observations in pregnancy because of acute appendicitis in 9 cases. Diagnosis is difficult because of the aspecificity and the alterations both of the site of symptoms and clinical manifestations, particularly during the last period of gestation. As there is an upward displacement of the viscus by the pregnant uterine. Notwithstanding the use of some not invasive methods, such as graded-compression sonography, the diagnosis is always effected by the clinical examination. Surgical treatment is always possible in the presence of acute appendicitis, as pregnancy isn't a reason for delay. The maternal mortality is at a zero level, the fetal one varies from 2% to 43% in cases of perforated appendicitis.

In vitro protein-binding characteristics of delavirdine and its N-dealkylated metabolite

This study was performed to determine delavirdine protein-binding characteristics as well as those of its N-dealkylated metabolite (N-DLV). Initial studies of 36 microM delavirdine and 30 microM N-DLV in solutions of plasma, albumin 4 g%, alpha-1-acid glycoprotein (AAG) 100 mg% or immune globulin (IVIG) 5 g% were conducted. Delavirdine (12, 36 and 73 microM) and N-DLV (10, 30 and 60 microM) were then studied alone and in combination in plasma and various concentrations of albumin. Studies were done in triplicate using equilibrium dialysis. The mean delavirdine fraction unbound (fu) in plasma, albumin, IVIG and AAG was 0.013, 0.033, 0.752 and 0.912 while the mean fu of N-DLV in these same protein solutions was 0.139, 0.195, 0.329 and 0.359. In plasma and albumin, a greater fu was observed at higher delavirdine concentrations and no significant changes in fu were noted with the addition of N-DLV. An increase in delavirdine fu was noted as the albumin concentrations decreased. The fu of N-DLV increased significantly as the concentration of albumin decreased as well as with decreasing N-DLV concentration. The potential implications of extensive delavirdine binding to plasma proteins, primarily albumin, are discussed.

Didanosine measurement by radioimmunoassay

Didanosine is commonly prescribed as monotherapy or as part of a combination regimen for patients with human immunodeficiency virus infection. The use of lower doses, either as part of a combination regimen or as a result of dose reduction secondary to clinical intolerance, requires that a sensitive assay method be available for either traditional or population-based pharmacokinetic evaluations. We evaluated a radioimmunoassay technique with a standard curve range of 0 to 100 ng/ml in human plasma, urine, and cerebrospinal fluid and assessed its accuracy and precision for use in pharmacokinetic studies.

[Acute cholecystitis: timing of surgery]

The authors report their own experience about 156 cases of acute cholecystitis observed between January 1991 and October 1992. The most part of the patients were between 30 and 65 years old (84 cases observed). In 27 cases, for the positive evolution of the pathology, it was put on practice a non operative treatment. The other 129 cases were treated surgically. The patients with lithiasic cholecystitis were 148; those affected by non lithiasic cholecystitis were 5; and 3 of them presented an acute cholecystitis as a manifestation of a carcinoma. Between the various diagnostic methods, the echography, executed in emergency, is considered as an indispensable one, for having changed completely the diagnostic approach. It is discussed, particularly, the timing of surgery, an aspect able to influence considerably the therapeutic iter and its results. There are analysed the criteria for whom some authors are favourable to a medical treatment of the acute cholecystitis, postponing the operation, while other of them are favourable to an early surgical treatment. The authors' casuistry put in evidence 110 operations effectuated in emergency (< 12 hours), 19 operations after an 12-72 hours interval, no operations at a long distance (1-10 months). The results are to be considered satisfactory: 1 deceased (on 129 operated cases, 0.78%); 10 immediate complications (7.75%): 8 suppurations of the wound, 1 biliar fistula and 1 internal hemorrhage after video-laparoscopic operation; 2 late complications (1.55%): they were relapsing gallstones. The aim of this work is to offer a contribution to codification of the treatment of the acute cholecystitis, on the ground of the acquired experience.

[Strangulated laparoceles. Our experience]

The authors present their own experience of emergency in strangulated laparoceles. Between January 1984 and June 1992 they treated at the Division of Emergency Surgery of the Hospital "A. Cardarelli" in Naples 133 cases of laparocele, 63 of which were strangulated. 48 of the 63 cases were treated by simply vertical or transversal laparoplasty ("waistcoat"); in 4 cases a direct plastic surgery; was executed in 11 cases a synthetic patch was used: in 2 cases a Teflon prosthesis was used; in one case a double prosthesis: a reabsorbable Vicryl patch internally and an external Marlex reticulated; in 8 cases a Marlex prosthesis. Moreover in most cases, before the laparoplasty of the abdominal wall operations of viscerolysis, were carried out intestinal and/or epiploon resection because of ischemia, colostomy, a Hartmann (one case). Of the 11 patients treated with synthetic patches, only 4 presented local complications: a seroma, two suppurations of the wound and a skin necrosis. These complications were treated with a medical therapy. In no case it was necessary to remove the prosthesis, as there were no general complications or deaths. We have to underline that notwithstanding the great advances both in surgery and in prosthesis' materials, the problem of the strangulated laparocele still represent a great engagement for the surgeon. The main reasons are: concomitant pathologies ("eventration disease"') and complications. The complications may be local (infection of the wound) or general (cardiocirculatory and respiratory problems due the viscus reduction in the original abdominal cavity).(ABSTRACT TRUNCATED AT 250 WORDS)

Fifteen years of operation of a high-performance liquid chromatographic assay for prednisolone, cortisol and prednisone in plasma

A high-performance liquid chromatographic (HPLC) assay first described in 1979 has been modified and revalidated for the simultaneous determination of prednisone, cortisol and prednisolone in human plasma using betamethasone as an internal standard. Revisions include: mobile phase composition; use of a precolumn, automated injector, integrator, and computer software; improved sensitivity and quantitation; thorough investigation of stability, variation, and specimen type; and inclusion of suggested quality control criteria. Plasma-based drug standards are extracted with methylene chloride and washed with sodium hydroxide followed by a water wash. After evaporation of solvent and reconstitution with mobile phase, the extracts are then injected onto a silica gel column (Zorbax SIL) for chromatography with UV absorbance at 254 nm. Calculated limits of quantitation are 10 ng/ml and limits of detection are less than 5 ng/ml. Intra- and inter-day coefficients of variation for quality control samples for all three corticosteroids are less than 11.2%. Recovery and stability data are also provided. Several drugs that may be coadministered do not interfere with the analysis.

Multicenter comparison of tacrolimus (FK 506) whole blood concentrations as measured by the Abbott IMX analyzer and enzyme immunoassay with methylene chloride extraction

A multicenter comparison was made between the Abbott IMX and enzyme-linked immunosorbent assay (ELISA) procedures for analysis of tacrolimus (FK 506) in whole blood. Proficiency samples and 853 patient specimens obtained after various organ transplantations were assayed by 13 laboratories. Both groups of test samples yielded slightly lower (7 and 13%) values by the IMX method, but the difference is not clinically meaningful. The type of organ transplant was not a factor that contributed to assay variation. The Abbott IMX results were essentially equivalent to ELISA and considerably facilitates monitoring of FK 506 therapy.

Validation and quality assurance program for monitoring tacrolimus (FK 506) concentrations in plasma and whole blood

Tacrolimus (FK 506), an investigational immunosuppressant drug, is undergoing several trials for various transplantations where protocols call for monitoring plasma and/or whole blood 12-h trough concentrations. Initially, the FK 506 Central Laboratory (FCL) adapted an established enzyme immunoassay (EIA) for FK 506 in plasma and provided clinical monitoring services for hepatic transplantation trials. Within 1 year, 16 clinical sites participating in these trials began direct use of the immunoassay for plasma and whole blood. A five step validation sequence facilitated rapid training and implementation of proficient assay services. All laboratories utilized common reagents, standards, and procedures. Participation in a quality assurance program involved monthly analysis of the three proficiency unknowns supplied by the FCL and reciprocal analysis of five patient samples (cross-checks) by the FCL. The quality of the data produced was assessed by proficiency scores, bivariate regression analysis, and correlations that demonstrated the concordance of their assay results for FK 506 in plasma and whole blood.

Asymptomatic women at high risk of vertical HIV-1 transmission to their fetuses

OBJECTIVE

To identify how reliably CD4+ (helper) lymphocyte count and p24 antigenaemia can predict mother-to-infant transmission of human immunodeficiency virus type 1 (HIV-1).

DESIGN

Prospective study.

SETTING

University of Turin Center for Intravenous Drug Users (IVDU) and/or HIV-1 seropositive pregnant women.

SUBJECTS

Twenty-nine infants born to asymptomatic seropositive women from November 1985 to June 1991.

RESULTS

Seven children (24%) developed symptomatic infection, while 22 healthy seronegative children at the age of 18 months were considered uninfected. A CD4+ lymphocyte count persistently < 500/mm3 during pregnancy was associated significantly with the child's infection status with a relative risk (RR) of 11.4. (CI 1.58-82.05). A marked association (RR 13.6) (CI 1.93-95.72) was similarly detected between maternal antigenaemia and the risk of the child being infected. In a multivariate logistic analysis, crude and adjusted odds ratios (OR) of transmission were 27.0 (95% CI 2.5-291.2) and 35.6 (1.1-1159) for low CD4+ counts; 64 (3.2-1261) and 51.6 (2.5-1058) for p24 antigenaemia.

CONCLUSIONS

Asymptomatic HIV positive women with a CD4+ count below 500/mm3 or p24 antigenaemia are about ten times as likely to transmit the virus to their children. CD4+ lymphocytes decrease during pregnancy and a low CD4+ cell count early in pregnancy remains low up to delivery. Therefore knowledge that they have a low CD4+ lymphocyte count early in pregnancy may help women to decide whether or not to continue their pregnancy.

[Social differences in infant mortality in a longitudinal Turin study]

The Turin longitudinal study enables to study the one-year survival of children born to any member of the study population and to relate the still-born and infant mortality to the parents' census characteristics. In this paper 25,108 children, born between 1981 and 1985 of parents residents in Turin at the 1981 population census, were followed up with respect to one-year survival. The numbers of infant deaths have been observed according to parents' education, housing ownership, occupational status and professional position. Only parents' education showed consistent differential in the still-born and infant mortality risks, adjusted for maternal age.

[The diagnostic course in patients with hereditary ataxias and hereditary spastic paraparesis]

A postal questionnaire was sent to all patients affected by hereditary ataxias and hereditary spastic paraparesis resident in the province of Turin (Italy) to study their diagnostic process. A 61% response rate was obtained. The mean time interval between onset and diagnosis was 6 years (1 to 32 years). The percentage of late diagnoses dropped from 59% before 1959 to 19% after 1970, mostly because a reduction of the interval between symptom onset and the first contact with the general practitioner. The onset with dysarthria and ataxia led to earlier neurologic consultation, but the whole time requested for the diagnosis was not modified. A reduction of the time needed for the diagnostic process may be important to address the family to an early genetic counselling.

Monitoring FK 506 concentrations in plasma and whole blood

The FCL provides support for clinical trials of FK 506 in liver transplantation by monitoring drug concentrations in plasma and whole blood. The sensitive EIA method of Tamura et al was adapted for routine use. Extraction of drug from 300 microL plasma or 20 microL whole blood samples was carried out using MeCl. An alternative solid phase (Sep-Pak) extraction method was also tested. Nonlinear temperature-sensitive binding of FK 506 to red cells necessitates plasma separation from whole blood at 37 degrees C. The analytical procedure entails numerous steps and efforts were made to improve the accuracy of the method. Interday CVs of FK 506 in plasma (0.3 to 3.0 ng/mL) and whole blood (4 to 60 ng/mL) ranged up to about 20% during validation testing and are maintained below 30% during routine assay use. However, daily QC samples occasionally yield unexpectedly high FK 506 concentrations. The MeCl and solid phase extraction methods yield FK 506 concentrations that reasonably correlate but the MeCl method produces plasma concentrations that are about 30% lower. FK 506 is appreciably bound in red cells with a nonlinear WBPR of 20 to 50 at low plasma concentrations (0 to 2 ng/mL) and a ratio of about 11 at plasma concentrations above 5 ng/mL. This may complicate conversion from plasma to whole blood for routine therapeutic monitoring. The described procedures for FK 506 are being implemented at various clinical sites in the United States with the FCL providing assistance with a quality assurance program to assure intersite comparability of assays results.

Pharmacokinetics and pharmacodynamics of prednisolone in obese rats

The pharmacokinetics and pharmacodynamic response to prednisolone were examined in dietary-induced obese rats and matched controls. Pharmacokinetic parameters were examined in absolute and weight normalized terms. After an i.v. dose (range, 4.0-6.3 mg/kg) of prednisolone adjusted to achieve similar initial prednisolone plasma concentrations, the time course of glucocorticoid receptors in hepatic cytosol and hepatic tyrosine aminotransferase (TAT) activity were examined. Plasma prednisolone concentrations declined biexponentially with time. Mean (S.D.) for prednisolone plasma clearance normalized for total body mass (TBM) was 2.3 (0.9) liters/hr/kg in normal rats and 2.7 (0.7) liters/hr/kg in obese rats. The volume of distribution at steady-state averaged 0.82 (0.46) liters/kg of TBM in normal rats vs. 1.08 (0.40) liters/kg of TBM in obese rats. Base-line receptor levels for obese rats were 53% higher than control levels. A model to describe simultaneously kinetics and receptor-mediated dynamics was used to analyze the data and obtain estimates for the efficiency of TAT induction. This efficiency parameter in obese rats was 22% of controls, reflecting the innate degree of diminished TAT response. This decreased response in obese animals may indicate a need for joint pharmacokinetic/dynamic considerations in dosing obese individuals with corticosteroids.

Drug compliance and unreported drugs in the elderly

A random sample of 46 general practitioners of the Unitá Sanitaria Locale in Torino recruited 802 elderly outpatients and collected information about complaints and current drug treatment. Within a week each patient received a home interview and details were collected on drug compliance and use of drugs other than those reported by the general practitioners. On average, each patient was taking 3.6 drugs, of which 2.9 were correctly reported by the general practitioners and 0.7 were unreported. Among the most prescribed therapeutic groups there were drugs with a narrow therapeutic index (cardiovascular drugs, diuretics, psychotropic agents) and substances whose efficacy has never been fully documented ("cerebroactive-vasoactive" agents). Age and number of complaints were positively and significantly correlated with number of prescribed drugs. Nearly half of the sample (44.4%)--more frequently women and people with higher education--were taking one or more drugs not detected by the general practitioners, often benzodiazepines taken over a long period for anxiety or insomnia. Full compliance occurred for 81.5% of the prescriptions and 59.9% of patients were correctly taking all prescribed drugs. Compliance was lower for prescriptions of the general practitioners compared with other doctors' prescriptions (eg, hospital doctor, private doctor) and probability of taking correctly all the prescribed drugs decreased with the number of medicines concurrently taken. The most common reason for noncompliance was fear of side effects.

[The elderly and drugs: the possible role of a home visit in improving a "difficult relationship". I. The results of an epidemiological study of drug prescription and use by the elderly conducted in the area of local health unit No. 1-23 in Turin]

A random sample of 46 general practitioners of the Unità Sanitaria Locale in Torino recruited 802 elderly outpatients and collected information about complaints and current drug treatment. Within a week each patient received a home interview and details were collected on drug compliance and use of drugs other than those reported by the GP. On average, each patient was taking 3.6 drugs of which 2.9 were correctly reported by the GP and 0.7 were un reported. Among the most prescribed therapeutic groups there were drugs with a narrow therapeutic index (cardiovascular drugs, diuretics, psychotropic agents) and substances whose efficacy has never been fully documented ("cerebroactive/vasoactive"). Age and number of compliants were positively and significantly correlated with number of prescribed drugs. The most common reason for non-compliance was fear of side-effects.

Pharmacokinetics of single and multiple doses of ethinyl estradiol and levonorgestrel in relation to smoking

The effects of tobacco and oral contraceptive (OC) use (Ovral) on the pharmacokinetics of levonorgestrel (0.25 mg) and ethinyl estradiol (50 micrograms) were examined. Young women (n = 27) were grouped as follows: I: non-OC users/nonsmokers; II: OC users/nonsmokers; III: non-OC users/smokers; and IV: OC users/smokers. The apparent clearance of levonorgestrel in group I was 80.9 +/- 15.6 ml/hr/kg and the half-life was 19.3 hours. A significant decrease in levonorgestrel clearance was seen in the chronic OC users (groups II and IV). The apparent oral clearance of ethinyl estradiol was 1002 +/- 398 ml/hr/kg in group I and the half-life averaged 7.7 hours. Groups II and III showed decreased (not significant) clearance of ethinyl estradiol. Tobacco use had no effect on steroid pharmacokinetics in the non-OC users. Although chronic OC use did not affect ethinyl estradiol clearance, a joint effect of tobacco/OC use on enhancing clearance of ethinyl estradiol appeared to occur. A linear relationship was found between 24-hour trough serum concentrations and AUC values of both steroids that may facilitate population monitoring studies of OC exposure.

Disability and quality of life in hereditary ataxias: a self-administered postal questionnaire

A postal questionnaire was sent to 151 patients affected by Friedreich's disease (FD) and other hereditary ataxias (OHA) to study their disability and quality of life. A 79.5% response rate was obtained. A scoring system based on disability in walking, dressing, personal care, eating and speaking was developed and used. Walking was the most impaired activity. The degree of disability was similar between FD and OHA. Institutionalization, frequency of social contacts, work activity, recreational and social activities were influenced by disability.

Receptor-mediated pharmacodynamics of prednisolone in the rat

A pharmacokinetic/pharmacodynamic model describing receptor-mediated effects of prednisolone is presented. The basis of the model is the generally accepted mechanism of action of steroid hormones in which corticosteroids bind to cytosolic receptors forming steroid-receptor complexes, which are activated and translocated into the nucleus. There the complexes associate with specific DNA sequences and modulate the rate of transcription of DNA into specific RNAs that code for the synthesis of proteins that elicit biological responses. Prednisolone, 5 or 50 mg/kg, was administered intravenously to adrenalectomized rats. Total plasma, free plasma, CBG-free plasma, and liver prednisolone concentrations were measured simultaneously with free hepatic cytosolic glucocorticoid receptor concentrations and tyrosine aminotransferase (TAT) activity of the liver as a function of time. The association/dissociation kinetics of prednisolone binding to the glucocorticoid receptor were measured separately in vitro at 37 degrees C. Total plasma, free plasma, and CBG-free plasma prednisolone concentrations could be used equally well in the model to account for the time course of receptor concentrations and TAT activity. However, use of liver steroid concentrations resulted in an overestimation of receptor depletion. Steroid concentrations in plasma increased 20 to 30-fold with a tenfold increase in dose, but receptor occupancy and TAT activity over time increased about threefold. While prednisolone pharmacokinetics were dose-dependent, parameters describing receptor kinetics and TAT activity were constant at each prednisolone dose. The major determinants of receptor-mediated glucocorticoid activity are confirmed to be the availability of the receptor, drug-receptor dissociation rate, and corticosteroid persistence in the biophase.

Effects of ketoconazole on methylprednisolone pharmacokinetics and cortisol secretion

The disposition of methylprednisolone was examined in six normal subjects after the injection of 20 mg iv methylprednisolone sodium succinate. Disposition studies were performed both without and with ketoconazole, 200 mg/day, for 6 days. Ketoconazole increased the methylprednisolone AUC and mean residence time (by 135% and 66%, respectively) and decreased clearance (60%), the terminal phase slope, and the volume of distribution. These findings are typical of macrolide antibiotic alteration of methylprednisolone disposition and consistent with reports of inhibition of drug metabolism by ketoconazole. Methylprednisolone reduced the 24-hour cortisol AUC by 44%, but morning cortisol concentrations returned to normal. Ketoconazole with methylprednisolone further reduced the 24-hour cortisol AUC and suppressed morning cortisol concentrations. Thus ketoconazole inhibits methylprednisolone disposition and extends the adrenal suppression effects of this corticosteroid.

Esophageal motor abnormalities in children with gastroesophageal reflux and peptic esophagitis

Esophageal motility was studied in 26 children with gastroesophageal reflux. In 11 patients (group A), esophagitis was severe; in the remaining 15 (group B), either mild or no microscopic changes were found. Lower esophageal sphincter pressure and amplitude, as well as velocity and duration of esophageal pressure waves, were manometrically measured. All patients underwent a 12-week intensive antacid course. Manometric tracings, blindly read, were compared with those of 16 age-matched children with emesis without proven reflux (group C). Among the variables analyzed, amplitude of the motor waves was significantly lower in patients with severe esophagitis than in group B and C patients (P less than 0.01). Nonspecific motor defects (simultaneous, broad-based, double-peaked waves) were more commonly present in group A. At the end of therapy, symptoms had either disappeared or significantly improved. Endoscopic and histologic studies showed disappearance of the severe inflammatory changes. Manometry, repeated in patients with cured severe esophagitis, showed normalization of the amplitude and significant decrease of the nonspecific motility abnormalities. We conclude that severe gastroesophageal reflux disease in children causes esophageal motor dysfunction, resulting from esophageal inflammation. The occurrence of esophageal motility disorders only in patients with severe esophagitis and its disappearance after therapy may account for the favorable course of reflux disease in infancy.