Preliminary report of localization of spinal cord blood supply by hydrogen during aortic operations

One source of paraplegia after aortic operations is the failure to reattach the spinal cord blood supply, the origins of which are not evident at operation. This report is concerned with a rapid new method of identifying these vessels intraoperatively. In 9 pigs, a specially designed catheter with platinum and stainless steel electrodes was inserted intrathecally. Saline solution saturated with hydrogen was injected sequentially into arterial ostia at T-15 to L-4 inclusive, and the generated current impulses from the conditioned platinum electrode were recorded. Of 90 potential segmental arteries supplying the spinal cord, 28 gave rise to spinal radicular arteries. Hydrogen-induced current impulses correctly located 25 of the radicular arteries and all those larger than 180 microns in diameter. When injected with indigo carmine, the vessels localized by the hydrogen-induced current impulses filled the entire anterior spinal artery from the low thoracic to the sacral region, whereas injection of the other vessels did not show filling. After refinement and testing for safety, this method has been employed clinically to rapidly localize and reattach routes of critical cord circulation.

Development of aneuploidy in experimental oral carcinogenesis

Using the rat model of oral carcinogenesis in which cell lines were derived from tissue after in vivo and in vitro treatment with the carcinogen 4-nitroquinoline-N-oxide (4NQO), we have shown that aneuploidy is generally associated with the ability of cells to form colonies in an anchorage-independent environment and to form tumours in athymic mice. In one cell line derived from 4NQO treatment in vitro, there was evidence that aneuploidy was an early marker, preceding anchorage independence and tumorigenicity in athymic mice. However, this was an inconsistent finding in other cell lines and the use of aneuploidy as an early marker of pre-malignancy should be treated with caution.

Presynaptic calcium currents recorded from calyciform nerve terminals in the lizard ciliary ganglion

Electron microscopic examination of ciliary ganglion from Anolis carolinensis shows large calyciform presynaptic nerve terminals ending on ganglion cells. Intracellular records were obtained from the terminals, and membrane currents were recorded with the single-electrode voltage clamp technique. After block of Na+ currents with tetrodotoxin, depolarization of the terminals produced inward currents that disappeared when extracellular Ca2+ was removed, and increased in magnitude and duration when competing outward currents were blocked by intracellular Cs+. Thus it is possible, with this preparation, to record and characterize Ca2+ currents presumably associated with neurotransmitter release.

The production and characterisation of monoclonal antibodies against human prolactin and the development of a two-site immunoradiometric assay

Monoclonal antibodies against human prolactin (PRL) have been produced and characterised and used to develop a sensitive two-site immunoradiometric assay (IRMA). Nine anti-PRL monoclonal antibodies were assessed for reactivity in immunoblotting experiments with PRL, hPL, hGH and pituitary gland extract. There was no detectable crossreactivity with hPL or hGH. In liquid phase radioimmunoassay (RIA) studies using three of the antibodies there was no detectable crossreaction from hPL or hGH. Five antibodies were positive in immunocytochemical studies using sections of human pituitary gland. Using FPLC purified monoclonal antibodies, a two-site IRMA was developed that could assay PRL over the range 17.5-3500 mIU per litre and was readily adapted to assaying serum samples from patients. The two-site IRMA could be performed within one day without loss of sensitivity and has potential as a rapid and simple method for screening clinical samples.

Effects of ethanol in an open field apparatus: modification by U50488H and WIN 44441-3

The effects of U50488H, a kappa agonist, and WIN 44441-3, a kappa antagonist, and their modification of the effects of ethanol, on the behavior of rats in a modified open field apparatus, was examined. Crossover activity was increased by U50488H. Headpoke activity was decreased by WIN 44441-3 and increased by U50488H. Rearing activity was increased by WIN 44441-3 but was not affected by U50488H. The effect of both drugs was dose related, with the largest doses having no effect. Ethanol (0.5 g/kg) stimulated crossover activity while it depressed rearing, headpoke and corner activities; except for crossover activity the 2.0 g/kg dose of ethanol depressed these activities. Pretreatment with WIN 44441-3 (0.5 mg/kg) potentiated the stimulant effect of ethanol on crossover activity and partially reversed the depressant effect of ethanol on rearing and headpoke activities. U50488H potentiated the ethanol-induced depression of headpoke and reversed the depression of corner activity. Pretreatment with U50488H had no effect on ethanol's action on crossover and rearing behaviors. Our results indicate that kappa opiate receptors may mediate some behaviors exhibited by rats in a modified open field apparatus. Activation of these receptors increases locomotor and headpoke activity but had no effect on rearing activity. Furthermore, the 0.5 g/kg dose of ethanol has differential effects on different measures of open field behavior, while the 2.0 g/kg dose was largely depressant. Our data suggest that some of these effects of ethanol may be mediated via kappa opioid receptors.

Intertypic genomic rearrangements of poliovirus strains in vaccinees

In vivo intertypic RNA recombination has previously been observed in excreted type 3 poliovirus isolates from a normal asymptomatic primary vaccinee. This study examines isolates from additional primary vaccinees to determine whether intertypic recombination is a general occurrence in excreted polioviruses. T1 RNase oligonucleotide finger-printing and limited dideoxy primer extension RNA sequencing demonstrated no evidence of intertypic recombination among type 1 or type 2 excreted strains. However, vaccinees excreting type 3 strains for long periods of time eventually produced recombinant strains involving either type 1 or type 2 poliovirus. Moreover, a characteristic time course of appearance of excreted type 3 intertypic recombinant polioviruses was established. Type 3/type 1 and type 3/type 2 recombinant strains appeared at Days 10-11 with a single crossover site in the gene for nonstructural protein 2C. Type 3/type 2/type 3 complex recombinant strains with an additional crossover site in the polymerase gene replaced type 3/type 2 strains at approximately Day 28. A significant portion of the genome of the type 3 Sabin vaccine strain is thus replaced during long-term excretion by vaccinees, and the appearance of some genomic arrangements coincided with a base deletion at the 3' terminus.

Use of a trickle irrigation system to distribute entomopathogenic nematodes (Nematoda: Heterorhabditidae) for the control of weevil pests (Coleoptera: Curculionidae) of strawberries

An established trickle irrigation system was used to distribute entomopathogenic nematodes for the control of Otiorhynchus sulcatus and Phlyctinus callosus in a commercial strawberry planting. This technique facilitated the rapid distribution of the nematodes to strawberry plants grown under plastic mulch. Variation in the distribution of nematodes was observed, both within the treatment area and on the soil surface immediately after application. Four weeks after the application of 48 000 and 80 000 infective stage Heterorhabditis heliothidis per plant, weevil survival (mean number of live larvae and pupae) was reduced by 59% and 25% compared with untreated plants.

DNA sequence of the D-serine deaminase activator gene dsdC

We have determined the DNA sequence of dsdC, the gene that encodes the D-serine deaminase activator protein of Escherichia coli K-12. The sequence contains a single open reading frame that terminates in a UGA codon. One the basis of the size of the protein, 33 kilodaltons, and the amino acid sequence encoded by the open reading frame, we identified a likely translation initiation codon 731 base pairs upstream of the translation initiation codon for the divergently transcribed D-serine deaminase gene. There is a broad range of codon usage, not surprising in view of the weak expression of the gene. The N-terminal two-thirds of the activator is arginine-lysine rich and quite polar; the remainder is more neutral. The segment of the protein that seems most likely to have potential to form the helix-turn-helix structure characteristic of DNA-regulatory proteins is located near the end of the polar region. The protein contains a region with significant homology to lambda attB.

Hepatic intra-arterial adriamycin in metastatic leiomyosarcoma: exploiting the steep dose-response curve

We report a case of extensive leiomyosarcoma of the liver that failed on systemic Adriamycin. Hepatic intra-arterial chemotherapy with Adriamycin has resulted in a lasting clinical remission. This report illustrates the importance of the dose-response curve of drug to tumor in regional chemotherapy as with Adriamycin used in sarcoma, and the need to further explore such therapy in moderately chemosensitive tumors that are surgically unresectable for anatomic reasons.

Differential binding of erythroid and myeloid progenitors to fibroblasts and fibronectin

Using a novel coverslip-transfer culture technique, we recently demonstrated that primitive erythroid burst-forming units (BFU-E) can migrate, proliferate, and differentiate in intimate association with stromal fibroblastoid cells in the presence of serum proteins and erythropoietin. No other exogenous hemopoietic growth factors are required. Most of the colonies that develop in this system are very large erythroid bursts, and very few granulocyte-macrophage (GM) colonies are observed. In this report, we present data indicating that the predominance of erythroid burst colonies in this culture system is due to preferential binding of primitive erythroid progenitors to the stromal fibroblastoid cells and not to differential stimulation of these erythroid progenitors by these cells. We next show that the binding of BFU-E to stromal cells is blocked by anti-fibronectin antibodies. Finally, we demonstrate the preferential binding of BFU-E to fibronectin by using glass coverslips or Petri dishes coated with purified human plasma fibronectin. The binding is blocked by a monoclonal antibody specific for the cell-binding domain of fibronectin. We conclude that: primitive erythroid progenitors bind strongly whereas G and/or M progenitors (CFU-G/M) bind only weakly to fibronectin; primitive erythroid progenitors bind to the cell-binding domain on the fibronectin molecule; and erythroid progenitors and precursors remain bound to fibronectin throughout differentiation.

Hydrophobic interaction chromatography of incompletely methylated transfer RNA from Escherichia coli on octyl-sepharose

Phenylalanine-specific transfer RNA from methionine-starved relaxed Escherichia coli K12 separates into two components when chromatographed on Octyl-Sepharose. The difference in elution between the two tRNAs has been shown to depend on the methyl group in the highly modified 2-methylthio-N-6-isopentenyladenosine. The first eluted tRNAPhe lacks this methyl group, while the last eluted tRNAPhe is fully methylated. Other differences in the modification patterns have no effect on the elution from Octyl-Sepharose. The elution pattern of tyrosine- and serine-specific tRNAs, also normally containing ms2i6A, is similar.

Early exposure to delta 9-tetrahydrocannabinol influences neuroendocrine and reproductive functions in female rats

Sexual differentiation of the rat brain is affected by certain compounds administered during the neonatal period. We evaluated the effects of exposure to THC during the critical period of sexual differentiation of the female rat brain on postpubertal estrous cycles and brain neurotransmitter levels. Newborn female rats were injected either with vehicle (oil) or with different doses of THC (0.38; 1.9 or 3.8 mg/100 g) subcutaneously during the first 5 days after birth. The rats were examined daily by vaginal lavage smears from 3 to 10 months of life for phases of estrous cyclicity. The animals were then sacrificed and the anterior hypothalamus preoptic area (AHPOA) and medial basal hypothalami (MBH) were collected, processed and the methionine-enkephalin (met-enkephalin), beta-endorphin-like immunoreactivity (beta-end LI), LHRH and substance-P were measured by radioimmunoassays. In addition, serum LH and prolactin levels were measured by radioimmunoassay. Compared with the control rats, the rats perinatally exposed to THC exhibited either constant metestrus diestrus type vaginal smears or irregular estrous cycles. In the THC-treated animals, the met-enkephalin and beta-end LI levels were lower in the AHPOA and higher in the MBH. The LHRH levels of THC-treated rats were significantly lower in the MBH. The substance-P levels were significantly lower in the AHPOA of THC treated animals. In the THC-treated rats, serum LH was low but, the prolactin levels were not significantly different from the control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of acute and subchronic delta 9-tetrahydrocannabinol administration on the plasma catecholamine, beta-endorphin, and corticosterone levels and splenic natural killer cell activity in rats

The effect of acute (1 day) or subchronic (25 days) treatment with delta 9-tetrahydrocannabinol (THC), the major psychoactive constituent of marihuana, on plasma norepinephrine (NE), epinephrine (E), corticosterone, beta-endorphin (beta-end), and splenic natural killer (NK) cell activity of the rat was studied. Groups of animals received subcutaneously, either THC in corn oil + saline (3 mg THC/kg); oil + saline; or THC + naloxone (2 mg naloxone/kg and 3 mg THC/kg). Acute injection of THC with or without naloxone did not significantly change plasma levels of NE, E corticosterone, beta-end, or the NK cell activity. However, subchronic treatment with THC significantly reduced plasma levels of NE, E, corticosterone, and NK cell activity, compared to controls. The plasma beta-end levels were significantly elevated in the THC-treated animals. In the THC + naloxone group of animals, the plasma hormone levels (corticosterone and beta-end) were similar to control levels and the NK cell activity was significantly higher than in THC-treated animals. These results indicate that subchronic exposure to THC results in suppression of splenic NK cell activity. The interaction of THC with the endogenous opiate system appears to be a contributing factor leading to the NK cell suppression in rats. A direct suppressive action of THC or its metabolites on the NK cell is not ruled out by this study.

Gene organization and regulation in the qa (quinic acid) gene cluster of Neurospora crassa

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Surgical problems in the management of giant fibroadenoma of the breast

Giant intracanalicular fibroadenoma is reported to be the most common cause of a massive, deforming enlargement of one breast in the female adolescent. It occurs infrequently and has a varied histopathologic pattern. It is suggested that obstetricians and gynecologists should have an awareness of this potentially malignant tumor of the breast with its associated problems of diagnosis and surgical management. Consideration of these huge breast tumors in relation to other similar breast lesions is presented in order to emphasize differential characteristics and treatment.

Inactivation of the beta-adrenergic receptor in cardiac muscle by dithiols

The effect of sulfhydryl reagents on binding of the beta-adrenergic antagonist (-)-[3H]dihydroalprenolol hydrochloride [-)-[3H]DHA) to a microsomal fraction of rabbit ventricular muscle was studied. Incubation with the disulfide reducing agents dithiothreitol (DTT), 2-mercaptoethanol, and reduced glutathione resulted in loss of (-)-[3H]DHA binding. At 500 microM DTT, less than 50% of specific binding activity remained; at 100 mM, binding was completely eliminated. 2-Mercaptoethanol and reduced glutathione were less effective than DTT at inhibiting binding activity. The total binding capacity (Bmax) decreased from 155.4 fmol mg-1 of protein, in the absence of DTT, to 92.4 and 77.5 fmol mg-1 at 0.25 and 0.7 mM DTT, respectively. The equilibrium dissociation constant (KD) increased from 7.6 nM, in the absence of DTT, to 10.3 nM at 0.25 mM DTT and to 20.8 nM at 0.7 mM DTT. Thus, DTT-induced decline in (-)-[3H]DHA binding results from a decrease in both the number and affinity of membrane binding sites for the tracer. Receptors could be protected from DTT inactivation by preincubation with beta-adrenergic ligands. Oxidants could not reverse inactivation, with the exception of o-iodosobenzoate which was only partially effective. Thus, the beta-adrenergic receptor of rabbit ventricular muscle contains essential disulfide moietie(s) which can be inactivated by reducing thiols.

The effect of an academic examination on salivary norepinephrine and immunoglobulin levels

Forty-six college students provided saliva samples just after taking an examination, one hour and 45 minutes later, and several days later, at a period of rest. As compared with baseline levels, the power stress of an examination was associated with an increase in salivary immunoglobulin A (S-IgA), a measure of B-cell immune function, and with an increase in norepinephrine (NE) concentrations in the saliva. The increase in NE was greater for those for whom n power was greater than n affiliation rather than for those for whom the reverse was true. Greater increases in, and levels of, NE at the examination and after were associated with greater subsequent drops in S-IgA, which reached below baseline levels for those for whom n power was stronger. The examination stimulated adrenergic activity, which in the long run depressed immune function for those with a strong power motive who had been most aroused adrenergically by the examination.

A monokine stimulates production of human erythroid burst-promoting activity by endothelial cells in vitro

Conditioned media were prepared from human peripheral blood monocytes and human umbilical vein endothelial cells. These media were assayed for erythroid burst-promoting activity (BPA) using human peripheral blood monocyte-depleted mononuclear cells as targets and assessing the stimulatory effect of the conditioned media on growth of early erythroid progenitor cells. Both monocytes and endothelial cells produced modest amounts of detectable BPA. Addition of varying concentrations of media conditioned by monocytes to plateau concentrations (5-10%) of media conditioned by endothelial cells had no additive effect. Endothelial cells incubated in the presence of 50% monocyte-conditioned medium produced 2.5- to 6.6-fold more BPA than did endothelial cells incubated only in control tissue culture medium. In contrast, endothelial cell conditioned medium did not stimulate increased BPA production by monocytes. Neither neutrophil- nor marrow fibroblastoid cell-conditioned medium stimulated BPA production by endothelial cells. Therefore, both monocytes and endothelial cells produce BPA. Moreover, monocytes produce a monokine that, in turn, stimulates the production of BPA by endothelial cells. Inasmuch as a monokine also has been shown to stimulate production of granulocyte-macrophage colony-stimulating activity, we propose that monocytes play a critical role in regulating the production of humoral regulators of the very early stages of hemopoietic cell differentiation.

Effect of delta 9-THC on brain and plasma catecholamine levels as measured by HPLC

The effects of chronic administration of delta 9-tetrahydrocannabinol (delta 9-THC) on the plasma and brain catecholamine (CA) levels were measured using high performance liquid chromatography-electrochemical detection (LC-EC) system. Intact male rats were injected daily with vehicle (50 microliter oil) or with delta 9-THC (3 mg/kg body wt) over a period of 25 days. Trunk plasma and tissue from preoptic area (POA) and mediobasal hypothalamus (MBH) were collected and catecholamine levels were detected by LC-EC system coupled to an electronic integrator. Alumina extract of tissue and plasma samples, spiked with the internal standard (dihydroxybenzylamine), were injected into the LC-EC system; the CA were chromatographed and eluted within 12 minutes using sodium phosphate buffer as the mobile phase. delta 9-THC treatment resulted in a significant decrease in plasma and MBH levels of norepinephrine (NE), epinephrine (E), POA levels of NE; and significant increases in MBH levels of dopamine (DA) and dihydroxyphenylacetic acid (DOPAC). Our study indicates for the first time that delta 9-THC treatment significantly alters not only the POA and MBH CA levels, but also the plasma CA levels.

The syndromes of pancreatic pseudocysts and fluid collections

The clinical and radiologic spectrum of pseudocysts associated with alcohol-induced pancreatitis is wide and variable. Several illustrative cases which delineate the diversity of syndromes that occur with pseudocysts are presented. A classification is proposed to facilitate a more coherent approach to the concept of pseudocysts and is based on the clinical presentation. Thus, in acute pancreatitis duct disruption and enzyme activation may result in intrapancreatic or extrapancreatic fluid collections. In calcifying chronic pancreatitis duct obstruction may result in pseudocysts of the head, body, or tail of the pancreas, which can enlarge and penetrate into extrapancreatic sites. This subdivision will assist in elucidating the natural history of pseudocysts and pancreatic fluid collections. Furthermore, it may establish new guidelines for diagnosis and therapy.

Enhanced T helper cell function for the spontaneous production of IgM rheumatoid factor in vitro in rheumatoid arthritis

Co-culture experiments between T and B cells from normal subjects and rheumatoid arthritis (RA) patients were performed in order to assess the immunoregulatory effects of T cells on spontaneous production of IgM rheumatoid factor (IgM-RF). Cultures of normal B cells with normal, autologous or allogeneic T cells failed to synthesize IgM-RF. In contrast, RAT cells promoted IgM-RF production from normal B cells as well as from RA B cells. The 'helper' effect of T cells from RA patients for IgM-RF production was not HLA-DR4 restricted and could not be accounted for by an allogeneic effect. These observations suggest that activated T helper cells may contribute to the production of IgM-RF in RA.

The spread of oesophageal cancer: an evaluation of clinical, barium and computed tomography assessments

One hundred and three patients with proven oesophageal cancer were evaluated prospectively by clinical examination, upper gastro-intestinal barium studies and computed tomography (CT). The accuracy of each method in assessing the extent of disease was determined by correlation with findings at bronchoscopy (100 patients), thoracotomy (26 patients) and laparotomy (63 patients). The results indicated that CT will accurately demonstrate mass invasion of cancer into mediastinal structures. But the absence of fat-planes on CT is the least reliable indication of spread into peri-oesophageal soft tissues. Early mediastinal infiltration is best assessed by analysis of the oesophageal axis on barium swallow and the patient's symptoms. Computed tomography is not helpful in the diagnosis of mediastinal node metastases. Barium studies of the proximal stomach will accurately identify (and CT reliably exclude) local tumour extension into the stomach. CT can frequently fail to detect malignant abdominal lymphadenopathy in cachexic patients.

Multiresidue Gas Chromatographic Method for Determining Organochlorine Pesticides in Poultry Fat: Collaborative Study

A gas chromatographic electron capture detector method is described for the quantitative determination of organochlorine pesticide residues in poultry fat. The samples are rendered and cleaned up using automated gel permeation chromatography. The collaborative samples consisted of 10 fortified samples and one incurred residue sample, all in duplicate. Fortification levels ranged from 0.15 to 1.0 ppm for a-BHC, lindane, cis- and frans-chlordane, octachlor epoxide, o,p' and p,p'-DDT, p,p'-DDE, p,p'-TDE, hexachlorobenzene, heptachlor epoxide, dieldrin, endrin, methoxychlor, mirex, and toxaphene. The average recovery was 91.9% with a range of 81-102%. The ranges of coefficients of variation were: CVo = 3.39-14.79%; CVL = 0-16.6%; and CVx = 5.82-19.0%. The results indicate accuracy and precision comparable to other official methodology. The method has been adopted official first action.

Computed tomography of intraabdominal abscesses

A total of 78 patients were subjected to computed tomography (CT) over a period of 18 months. CT proved extremely accurate in the diagnosis of intraabdominal abscesses and in estimating the extent of spread. The series included many examples of amoebic and hydatid abscesses with unusual presentations and appearances. The commonest appearance of abscesses on CT was a low-density mass with peripheral rims after the administration of intravenous contrast media, followed by gas-containing low-density lesions which were regarded as showing characteristic features of abscess formation. Pitfalls in the CT appearance of abdominal abscesses were many and correlation with the clinical presentation was essential for diagnosis. The greatest value of CT lay in the rapidity of diagnosis.

CT appearance of bladder malakoplakia

The computed tomographic (CT) findings of malakoplakia of the bladder are presented. Although the CT findings were not considered specific for this condition, the presence of a solid bladder mass with or without extension beyond the confines of the bladder in a young woman with urinary tract infection should suggest the possibility of this diagnosis.

Spontaneous and pokeweed mitogen induced in vitro immunoglobulin and IgM rheumatoid factor production by peripheral blood and synovial fluid mononuclear cells in rheumatoid arthritis

Enzyme-linked immunosorbent assays (ELISA) were used to measure IgG, IgM and IgM rheumatoid factor (IgM RF) production in supernatants of pokeweed mitogen (PWM) stimulated peripheral blood mononuclear cells (PBMNC) of patients with rheumatoid arthritis (RA) and controls. Spontaneous and stimulated IgG and IgM production by RA and controls was comparable, but spontaneous production of IgM RF was only observed in RA and was related to their drug therapy. A significant difference was found between PWM induced IgM RF production in RA and controls and also between patients on "second-line" and on nonsteroidal anti-inflammatory drugs (NSAID). In addition, spontaneous IgM RF production by synovial fluid cells was significantly higher than the paired PBMNC.

5'-Untranslated sequences of two structural genes in the qa gene cluster of Neurospora crassa

The coding regions of two genes (qa-2 and qa-3) in the qa gene cluster of Neurospora crassa have been localized by nucleotide sequence analysis combined with data on previously determined NH2-terminal amino acid sequences for the proteins that these genes encode. The start point of transcription for each of these genes has been determined by nuclease S1 mapping experiments with poly(A)+RNA isolated from quinic acid-induced cultures of N. crassa. The sequences of approximately 200 nucleotides 5' to the start point of transcription have been compared with each other and with those of other eukaryotes. The results show that neither of these regions for the qa-2 nor the qa-3 genes share any significant homology with sequences apparently conserved in higher eukaryotic promoters (-25 and -70 regions). However, the qa-2 and qa-3 sequences do show homology with each other in these regions. Comparison of the 5'-flanking regions of these Neurospora genes with those of several Saccharomyces cerevisiae genes reveals a number of similarities in the region preceding the translation initiation codons.

Lymphocyte studies in rheumatoid arthritis. V. Suppressor cell function in peripheral blood

Peripheral blood lymphocytes from 30 patients with rheumatoid arthritis and 14 controls were examined for suppressor activity by two different assays. These were the Concanavalin-A-induced and the short-lived suppressor cell assays. There was no difference in suppressor activity between patients and controls, the suppressor activity of HLA-DR3 positive patients was no less than that of non-DR3 patients. However, patients with nodules showed reduced suppression in the short-lived suppressor cell assay when compared with patients without nodules.

Gastric infarction: a complication of selective vasopressin infusion

This report describes a case of massive gastric hemorrhage, initially controlled by selective arterial vasopressin infusion. Infusion was followed by extensive necrosis of the gastric wall which necessitated subtotal gastrectomy. Gastric necrosis following arterial infusion is rare and in this case appears to be due to migration of the infusion catheter into a peripheral branch of the left gastric artery in a patient whose gastric circulation had been compromised by prior surgery. The complications related to the use of arterial infusion for the control of gastric hemorrhage are discussed and the literature is reviewed.

Crown ether catalysis of decarboxylation: a general survey of reactivity and detailed analysis of the triphenylacetate anion

The effect of 18-crown-6 ether 3 on the decarboxylation rate in THF of sodium salts of carboxylic acids formally derived from hydrocarbons has been investigated and these acids include 9-phenylfluorene-9-carboxylic acid, fluorene-9-carboxylic acid, phenylacetylene carboxylic acid, triphenylacetic acid, and diphenylacetic acid. Addition of equimolar 3 resulted in an increase in decarboxylation rate of 13- to 500-fold and there was a correlation between the decarboxylation rate and the pKa value of the product hydrocarbon.The decarboxylation of triphenylacetate was investigated in detail. The effect on reaction rate of cation (Li+, Na+, K+), crown ether concentration, water concentration, and solvent polarity has provided information as to optimum reaction conditions and has helped to clarify the reaction mechanism.

Nephrotoxicity of cephalosporin-gentamicin combinations in rats

TO STUDY THE POSSIBILITY THAT CEPHALOSPORINS AUGMENT THE NEPHROTOXICITY OF GENTAMICIN, GROUPS OF RATS WERE GIVEN FOUR HOURLY SUBCUTANEOUS DOSES OF: gentamicin (5 mg/kg), gentamicin plus cephalothin (100 mg/kg), gentamicin plus cefazolin (20 mg/kg), gentamicin plus cefazolin (50 mg/kg), gentamicin plus cephaloridine (50 mg/kg), or saline diluent for 15 days. Periodic measurements were made of urine volume, urine osmolality, urine protein excretion and lysosomal enzymuria, as well as blood urea nitrogen, creatinine clearance, and drug concentrations in renal cortex and medulla. Tissue was examined by light and electron microscopy. Enzymuria and proteinuria increased early in the course of all treatment groups, whereas urine osmolality declined. No distinct patterns of these variables were discernable among the groups. Gentamicin alone, gentamicin plus cephalothin, and gentamicin plus cefazolin (20 mg/kg) caused the same significant fall in glomerular filtrate rate from control values by day 15 (P < 0.05). Gentamicin plus cefazolin (50 mg/kg) and gentamicin plus cephaloridine failed to cause a decline in glomerular filtration rate compared with controls (P > 0.05). Gentamicin concentrations in renal cortex were 5 to 10 times higher than those in medulla in all groups. Cephaloridine and cefazolin (50 mg/kg) also displayed a gradient pattern in renal cortex, whereas cephalothin and cefazolin (20 mg/kg) did not. Cytosegrosomes with myeloid figures were characteristic ultra-structural changes seen in all groups; however, they tended to be smaller with less numerous myeloid bodies in the groups receiving gentamicin plus cephalothin, cefazolin (50 mg/kg), or cephaloridine. Cephalosporins did not augment gentamicin toxicity. High doses of cefazolin and cephaloridine protected kidneys from gentamicin nephrotoxicity. The protection may involve intracellular drug interaction within the renal cortex.

Experimental aminoglycoside nephrotoxicity

The nephrotoxicities of gentamicin and three other experimental aminoglycosides were compared at a single 60 mg. per kilogram per day dose in rats. Renal function, lysosomal enzymuria, and antibiotic concentrations in plasma, urine, and renal tissue were measured at regular intervals throughout the course of treatment. Kidney tissue was examined by light and electron microscopy in animals killed at intervals throughout the period of antibiotic administration. Proteinuria and enzymuria were early indicators of nephron dysfunction, whereas endogenous creatinine clearance declined later in the course of treatment. All animals were killed 24 hours after a previous antibiotic injection and displayed sustained renal tissue antibiotic concentrations which were 5 to 10 times higher than those in serum or urine. When assayed separately, renal cortical tissue had a fivefold greater antibiotic concentration than renal medulla. Light microscopy displayed necrosis of the pars convoluta of the proximal tubule. Electron microscopy revealed appearance of cytosegrosomes with myeloid bodies. It is possible that impaired cytoplasmic degradation of sequestered organelle membranes, resulting from aminoglycoside accumulation, is responsible for the myeloid body formation and subsequent tubular necrosis.

Enzymuria in gentamicin-induced kidney damage

To assess their potential value as early indicators of gentamicin-induced kidney damage, lysosomal hydrolases were measured in the 24-h urines of rats receiving 30 or 60 mg of gentamicin per kg per day for 15 days. Proteinuria, urine osmolality, blood urea nitrogen, and creatinine clearance were also measured. Kidney tissue was examined by both light and electron microscopy. Beta-galactosidase, beta-n-acetyl-hexosaminidase, and alpha-fucosidase were sensitive indicators and were significantly elevated above control values by day 3 at both doses (P < 0.01). Proteinuria, urine osmolality, and tests reflecting glomerular filtration rate were later indicators of nephron damage. Changes by light microscopy were detected on day 5. Necrosis was most prominent in the proximal convoluted tubules on day 10. Electron microscopy revealed numerous cytosomes with myeloid bodies within the proximal tubular epithelium on day 5. Lysosomal enzymuria appears to be an early manifestation of gentamicin nephrotoxicity and may possibly be related to the lysosomal abnormalities seen on electron microscopy.