Chronic caffeine administration exacerbates renovascular, but not genetic, hypertension in rats

The purpose of this study was to determine whether or not caffeine would exacerbate renovascular hypertension. Therefore, we examined the effects of chronic caffeine administration on arterial blood pressure in rats subjected to either unilateral renal artery clipping (2K-1C rats) or sham-operation. Animals in each group were randomly assigned to receive either 0.1% caffeine in their drinking water or normal drinking water, and systolic blood pressure was monitored for 6 wk. Caffeine markedly exacerbated the severity of hypertension in 2K-1C rats and caused histological changes consistent with malignant hypertension. 6 wk after surgery, systolic blood pressure, plasma renin activity, and creatinine clearance in control 2K-1C rats were 169 +/- 5 mmHg (mean +/- SEM), 4.4 +/- 0.5 ng AI X ml-1 X h-1, and 2.9 +/- 0.2 ml/min, respectively; as compared with 219 +/- 4 mmHg, 31.8 +/- 7.8 ng AI X ml-1 X h-1, and 1.4 +/- 0.3 ml/min, respectively, in 2K-1C rats receiving caffeine (all values were significantly different compared with control 2K-1C). Chronic caffeine administration did not alter systolic blood pressure, plasma renin activity, or creatinine clearance in sham-operated rats or spontaneously hypertensive rats. Chronic treatment with enalapril (a converting enzyme inhibitor) prevented the development of hypertension in control 2K-1C rats and caffeine-treated 2K-1C rats; however, withdrawal of enalapril precipitated a rapid rise in systolic blood pressure in caffeine-treated 2K-1C rats, but not in control 2K-1C rats. These experiments indicate that caffeine specifically exacerbates experimental renovascular hypertension and might worsen the hypertensive process in patients with renovascular hypertension.

Potassium

Potassium homeostasis is dependent on many physiologic and metabolic factors. Potassium level testing by the clinical laboratory can aid the emergency physician in planning treatment in suspected cases of potassium depletion or excess. Familiarization with indications for ordering tests of potassium level and correct interpretation of test results is essential for appropriate patient care.

The role of lymph node dissection for clinical stage I malignant melanoma of intermediate thickness (1.51-3.99 mm)

The survival times of patients who had an elective regional lymph node dissection was compared with that of those who did not undergo the procedure in a database of 72 patients with clinical Stage I melanoma of intermediate thickness (1.51-3.99 mm). All of the patients had been followed for 5 years or longer or until death. No significant differences were found in other reported prognostic factors, suggesting that the two groups were comparable. By multivariate analysis, a low mitotic rate, intermediate patient age, and the presence of an infiltrative lymphocytic response were found to be associated with favorable survival. There did not appear to be any association of elective regional lymph node dissection with survival; and it was concluded that such therapy should not be regarded as "standard" for clinical Stage I melanoma of intermediate thickness.

Antitrust aspects of exclusive contracts in medical imaging

Exclusive contracts between radiologists and hospitals may be more frequently scrutinized for antitrust violations because of the Hyde v Jefferson Parish Hospital District No. 2 case. In the Hyde case, the lower court decided antitrust law had been violated, and it was the first antitrust case about exclusive medical contracts to be reviewed by the U.S. Supreme Court. The case is a precedent for considering similar circumstances according to traditional business antitrust analyses such as per se violations, tying arrangements, group boycott, and market foreclosure. Areas that may be scrutinized for anticompetitiveness include hospital privileges when radiologists have exclusive contracts with the community's only hospital or provide services unique within an area, and physicians' access to scarce resources (e.g., computed tomography [CT], magnetic resonance [MR] imaging). Radiologists must understand antitrust implications of their hospital contracts; examine the terms of staff appointment, bylaws, and rights; and be able to guide their attorneys through contract negotiations.

Laser Doppler surveillance of the circulation of free flaps and replanted digits

In a series of 40 clinical free flaps and replantations the laser doppler technique has been used successfully for postoperative surveillance of circulation. A uniform flow pattern was obtained from all uncomplicated cases contrasting to the flow pattern seen in cases with thrombotic complication. The laser doppler continuously records flow of the microcirculation and is able to monitor blood flow in all types of free tissue transfer presently used as well as replantations. The laser doppler has effectively diagnosed two arterial thromboses with a characteristic flow pattern. It can distinguish venous from arterial occlusion. It can record flow in skin flaps which are difficult to judge clinically and in buried flaps, where no clinical observations are possible. The laser doppler should be used in conjunction with routine clinical observations.

Cancer of lymphatic tissues in cane-growing areas of Queensland

The mortality from leukaemias and lymphomas in a tropical urban region of Queensland (Townsville) and in the mainly tropical cane-farming regions of Queensland was investigated. It was found that, compared with the general population of Queensland, there were fewer deaths from neoplastic disease of the lymphatic tissues in women in both regions; that there were fewer deaths from neoplastic disease of the lymphatic tissues in men in Townsville, but not in the cane-growing areas; and that, during the period 1968-1981, there was a significantly lower number of deaths from leukaemia (13 deaths; SMR, 49; P less than 0.01) in women over 60 years of age in the cane-growing areas, which contrasted with a significantly greater number of deaths from leukaemia (61 deaths; SMR, 154; P less than 0.01) in men 60 years and over in the cane-growing areas.

Enteric pathogenic protozoa in homosexual men from San Francisco

The prevalence of enteric protozoa was studied in a survey conducted among 150 male homosexual patients in San Francisco. All patients were from a private practice in internal medicine. Each was asked to complete a questionnaire and to submit multiple stool specimens for examination. Of this group, 47% were positive for one or more potentially pathogenic intestinal protozoa; Entamoeba histolytica was found in 36%, Entamoeba hartmanni in 35%, Giardia lamblia in 5%, and Dientamoeba fragilis in 1.3%. Symptoms were unreliable as a diagnostic index of intestinal protozoan infection. Colonization rates could not be correlated with any specific sexual technique. The large number of homosexuals at risk, combined with the potential for difficulties in diagnosis and contact-tracing, indicate the possibility that enteric pathogenic protozoa will cause future health problems in this population.

Heart rate response to tilting in newborns in quiet and active sleep

The heart rate response to tilting was investigated in active and quiet sleep in 19 normal newborns (age 1-7 days) and 11 healthy premature infants (age 2-19 days). RR intervals were determined by computer from the ECG for 30-60 s periods immediately before and after each tilt. Term infants had a significant (p less than 0.005) decrease in RR interval for head-up tilting and significant (p less than 0.005) increase in RR with head down tilts. There was no significant difference in the magnitude of RR change between upward and downward tilt or between active and quiet sleep. For premature infants, the response to tilting was similar to that of the term infants, especially with allowance for the faster heart rates of the former. Respiratory rate changes were an important source of variability in the heart rate response to tilting and are likely the source of previous inconsistencies. Our results indicate that healthy newborns have a well-developed heart rate response to tilting, suggesting considerable maturity of neural control of heart rate.

Characterization of dog peripheral lymph lipoproteins: the presence of a disc-shaped "nascent" high density lipoprotein

The distribution, chemical, and apoprotein composition of plasma and peripheral lymph lipoproteins were compared in control and cholesterol-fed dogs. In both groups of animals, the agarose electrophoretic patterns of plasma and lymph lipoproteins were similar. In hypercholesterolemic dogs, beta-very low density lipoprotein, beta-migrating intermediate density lipoprotein, and HDLc were major components both in plasma and lymph, providing evidence for a potential interaction of these atherogenic particles with macrophages and other peripheral cells. The chemical composition and physical appearance of peripheral lymph HDL was markedly different from that of plasma HDL (high density lipoprotein), especially in the cholesterol-fed animals. Lymph HDL had a higher cholesterol to protein ratio and a markedly increased free cholesterol content (free cholesterol to cholesteryl ester ratio of 1.7 as opposed to 0.2 in plasma HDL in cholesterol-fed animals). The phospholipid content of lymph HDL was higher than that of plasma HDL, while the protein content was lower. A significant proportion of lymph HDL obtained from cholesterol-fed dogs was in the form of disc-shaped particles stacked in rouleau structures. Changes in plasma apolipoprotein concentrations due to cholesterol feeding were reflected in peripheral lymph to different degrees, depending largely on the relative size of the lipoproteins containing the individual lipoproteins. A considerable enrichment of lymph HDL with apoE and apoA-IV was observed by both immunochemical and electrophoretic methods. In lymph HDL from control and cholesterol-fed dogs, the apoE/apoA-I and apoA-IV/apoA-I ratios were several-fold elevated, compared to those of plasma HDL. It is concluded, therefore, that during cholesterol feeding a substantial portion of interstitial HDL is assembled de novo in the periphery as a crucial stage of reverse cholesterol transport to the liver. It is likely that further modification occurs upon entry to plasma and exposure to lecithin:cholesterol acyltransferase, possibly leading to generation of HDLc. Alternatively, these particles may be directly and rapidly removed by the liver.

Phenotypic characteristics of cells derived from precursors of human melanoma

Of 66 specimens from benign melanocytic nevi, including common acquired and congenital nevi, Spitz tumors (epithelioid cell nevi), and melanocytic nevi with dysplasia, 57 could be grown in tissue culture. The cultured cells were identified as melanocytes by the presence of premelanosomes and melanosomes. Cells from 28 of 32 nevus cultures grew in an anchorage-independent way in soft agar with a colony-forming efficiency between 0.001 and 1%. Clones derived from single cells and soft agar-selected colonies showed marked phenotypic heterogeneity, but all had a limited life span and did not undergo transformation in culture. These cells were nontumorigenic in nude mice. Cultured nevus cells expressed antigens present on melanoma but absent on normal fibroblasts and/or melanocytes as tested with monoclonal anti-melanoma antibodies. The anti-melanoma antibodies bound equally well to dysplastic, congenital, and common acquired nevi. Antigens are released by nevus cells similar to melanoma cells.

Melanoma of the male urethra: surgical approach and pathological analysis

Primary urethral melanoma in male subjects is rare and optimum therapy has not been established. We described a male patient with a primary urethral melanoma that arose in a precursor nevus and was treated by excision, bilateral groin dissections and postoperative radiation therapy. Urinary and sexual functions have been maintained. We review the previously reported cases of urethral melanoma in male subjects. The biologic relationship of melanoma to precursor lesions in mucosal sites is discussed.

Repeated histamine inhalation tests in asthmatic patients

Histamine inhalation tests were performed in 12 asthmatic patients using a 2-min tidal breathing inhalation technique. The tests were repeated on separate days with 30-, 60-, and 120-min intervals between inhalation tests. On another day the inhalation tests were repeated four times with 40-min intervals between tests. The geometric mean provocative concentrations of histamine needed to cause a 20% fall in forced expiratory volume in 1 sec (PC20) for the group on the latter study day were 1.67, 1.57, and 1.55 mg/ml (p greater than 0.25) indicating no change in sensitivity to inhaled histamine with repeated testing. The results suggest that cumulative dose-response curves for drugs potentially affecting the airways or antagonizing histamine can be constructed within 1 day using histamine inhalation tests. The data also suggested that an individual PC20 result may be sensitively assessed by comparing it to a +/- 2 SD range from the mean of a series of control or placebo PC20 values.

Specific immunoreactivity of hybridoma-secreted monoclonal anti-melanoma antibodies to cultured cells and freshly derived human cells

The specificities of monoclonal antibodies against melanoma cells were analyzed using radioimmunoassay, mixed-hemadsorption assay, and quantitative absorption on a variety of malignant and nonmalignant cells. Three of the six hybridoma-secreted antibodies bound to the majority of melanoma cell lines, melanoma tumors, and astrocytoma cell lines as well as to all normal and Epstein-Barr virus-transformed lymphocytes tested. The binding pattern coincides with the presence or absence of the DR antigen on human cells. Conversely, two other antibodies, 19-19 and Nu4B, detected two different antigens common to melanoma and astrocytoma cells only. Cloning of melanoma cells resulted in establishment of DR-positive and DR-negative clones, with the binding of Nu4B antibody retained in all.

The use of microvascular free skin-muscle flaps in management of avulsion injuries of the lower leg

The authors used microvascular free skin-muscle flaps to cover avulsion wounds in the lower leg of ten patients. There were three children and seven adults, ranging in age from 5 to 54 years. Vessels supplying gracilis (four) and tensor fascia lata (six) skin-muscle units were anastomosed to the anterior tibial (nine) and posterior tibial (one) vessels. The tensor fascia lata unit has a more constant anatomy and is preferred. Principles of management include: 1) early adequate, but conservative, debridement; 2) continuous bony stabilization; 3) preoperative arteriography; 4) anticoagulation; 5) recipient vessel identification in healthy uninjured tissue; 6) appropriate timing; 7) delayed bone grafting.

Combined carotid-vertebral vascular disease: a new surgical approach

Selected patients with vertebral basilar insufficiency may obtain symptomatic relief after carotid endarterectomy. The usual surgical approach is that of initially performing carotid endarterectomy, if appropriate, followed at a second operation by extrathoracic vertebral reconstruction. This surgical approach is based in part on the need for different surgical incisions to reconstruct the cervical carotid and vertebral arteries. We describe a new surgical approach that utilizes a single cervical incision for combined carotid-vertebral reconstruction.

Diagnosis of carotid artery stenosis: comparison of oculoplethysmography and Doppler supraorbital examination

Both Doppler supraorbital examination (OSM) and oculoplethysmography (OPG) were administered to 101 patients (202 arteries) to document the presence or absence of hemodynamically significant lesions of the internal carotid artery prior to angiography. There was no significant difference between the OSM and OPG with respect to diagnostic sensitivity or specificity, incidence of false-negative or false-positive results, and overall diagnostic accuracy. The diagnostic accuracy for the OSM and the OPG were 94.2% and 91.6%, respectively. In 171/202 (84.6%) arteries, the OSM and OPG were in diagnostic agreement, and the overall diagnostic accuracy of the combined tests was 97%. However, when the OSM and OPG did not agree (31/202 arteries, 15.4%), the diagnostic accuracy of neither the OSM nor the OPG was acceptable. Although the best diagnostic accuracy was obtained using two means of noninvasive cerebrovascular testing, in those instances where only one test may be available, the OPG would appear to be the test of choice. In those laboratories in which high diagnostic accuracy is obtained with the OSM, the addition of OPG testing will increase the overall diagnostic accuracy to a very high level. The presence of a midcervical bruit was found to have a very poor correlation with the incidence of hemodynamically significant stenoses of the internal carotid artery. Although both the OSM and OPG have minimal value in patients with symptomatic cerebrovascular disease, these tests play a very important role in screening patients for asymptomatic carotid stenosis or atypical cerebrovascular symptoms.

Microvascular osteocutaneous groin flap in the treatment of an ununited tibial fracture with chronic osteitis. A case report

A 37-year-old man with an ununited tibial fracture combined with a significant skin defect underwent a microvascular transfer of an island osteocutaneous flap of groin skin and iliac crest bone. The bone component of the flap was shown to be a living transplant by the observation of brisk cancellous bone bleeding when the flap was isolated on its vascular stalk; by rapid fracture healing (weight-bearing 15 weeks postoperatively); and sequential bone scan investigations. Various aspects of the flap blood supply, particularly to bone, are discussed, and reference is made to the use of a more suitable vessel system.

Construction and cloning of rat albumin structural gene sequences

A recombinant plasmid containing a DNA segment complementary to rat liver albumin mRNA has been constructed, cloned, and used to examine the organization of albumin gene. The 18S fraction of total liver poly(A)-containing RNA was copied into a double-stranded cDNA by avian myeloblastosis virus reverse transcriptase and Escherichia coli DNA polymerase I. The cDNA was inserted into the HindIII site of the plasmid pBR322 via the addition of specific oligonucleotide linkers. Recombinant plasmids were screened by hybrid arrest of mRNA translation and hybridization with specific cDNAs. Thereby, a plasmid was identified that contained a 1200-nucleotide insert corresponding to a segment adjacent to the 5'-terminal region of albumin mRNA. The inserted sequence was used as a hybridization probe to detect five EcoRI fragments of genomic DNA which encode albumin mRNA. These were compared to eight EcoRI fragments identified within the rat genome by albumin cDNA. We conclude that the albumin gene (or genes) is interrupted at more than one site in the coding DNA by intervening sequences. Furthermore, we were able to distinguish those fragments that encode the 5' and 3' ends of the mRNA.

Neurological prognosis after traumatic quadriplegia. Three-year experience of California Regional Spinal Cord Injury Care System

Between January, 1974, and December, 1976, 123 patients with traumatic quadriplegia were admitted to the California Regional Spinal Cord Injury Care System. The spinal cord injury resulted from gunshot wounds in five, from a stab wound in one, from neck injuries with no bone damage seen on x-ray studies in 10, and from fracture dislocations of the cervical spine in 107. One-year following-up information was available on 114 patients. Neurological impairment using the Frankel classification system was compared at 72 hours postinjury to the 1-year follow-up examination. Fifty of 62 patients with complete injury at 72 hours were unchanged at 1 year. Five of these 62 patients had developed motor useful function in the legs or became ambulatory by 1 year, but all had sustained serious head injuries at the time of their trauma making initial neurological assessment unreliable. Ten percent of all cases had combined head injury impairing consciousness. Among 103 cognitively intact patients, none with complete injury at 72 hours were walking at 1 year. Of patients with sensory incomplete functions at 72 hours postinjury, 47% were walking at 1 year; 87% of patients with motor incomplete function at 72 hours postinjury were walking at 1 year. Spinal surgery during the first 4 weeks postinjury did not improve neurological recovery. A method of analyzing neurological and functional outcomes of spinal cork injury is presented in order to more accurately evaluate the results of future treatment protocols for acute spinal injury.

The sleeve anastomosis in clinical microsurgery. Case report

Clinical use of the microvascular sleeve anastomosis in 6 elective free tissue transfers is reported. Arterial and venous anastomoses were performed. It was found that with the exception of the distal anastomosis of a vein graft to artery the sleeve anastomosis was simple and efficient. It was concluded that when the vessels to be anastomosed have suitable length and diameter the sleeve anastomosis may well be used. By its use time and effort can be saved, especially in cases requiring multiple anastomoses.

Purification of human interferon by antibody affinity chromatography, using highly absorbed anti-interferon

Antibodies against partially purified human leucocyte interferon (PIF) were bound to Sepharose 4B and crude interferons applied on this affinity column were purified, up to 8 x 10(5) interferon units (IFU) per mg protein in one step. Antibodies against PIF were absorbed with immobilized crude human leucocyte interferon bound to Sepharose, whereby antibodies against impurities were predominantly removed. Extensively absorbed antisera were coupled to Sepharose and used for antibody affinity chromatography of crude interferon preparations. Leucocyte and fibroblast interferons were purified in one step with around 100% recovery, up to 1 x 10(8) IFU per mg protein, and Namalva interferon up to 2 x 10(7) IFU/mg. SDS electrophoresis of affinity-purified leucocyte interferon revealed that the interferon activity appeared in two bands (19,000 and 23,000 D).

Pancytopenia induced by aminoglutethimide in the treatment of breast cancer

Aminoglutethimide is an investigational agent of proven benefit in the treatment of metastatic breast carcinoma. We report herein a case of aminoglutethimide-induced pancytopenia complicated by bleeding and gram-negative septicemia. Severe pancytopenia is a rare but important side effect of this new drug and is rapidly reversible when the agent is withdrawn.

Effect of respiratory syncytial virus infection of HeLa-cell macromolecular synthesis

Cells infected with respiratory syncytial (RS) virus eventually die but there appears to be no specific mechanism for shutting off cellular synthesis of macromolecules. DNA and RNA synthesis, as measured by the incorporation of labelled thymidine or uridine, do not begin to shut down until some time between 11 and 18 h after infection. By 18 h their rates of synthesis are reduced to approx. 50% for DNA and 35% for RNA. Protein synthesis continues throughout the course of infection at approximately the same rate. Synthesis of most of the cellular polypeptides also continues, but the distribution of polypeptides of high and low mol. wt. shifts. The increase in the proportion of those of high mol. wt. includes a peak that represents one of the seven previously identified virion polypeptides. Another consequence of RS virus infection is an increase in glucosamine incorporation, beginning near the end of the virus eclipse period (12 h after infection), which may be associated with virion glycoprotein synthesis. Polyacrylamide-gel electrophoresis of glucosamine-labelled cells reveals that at 18 h after infection two of the three previously identified virion glycoproteins are present.

Clinical, laboratory, and epidemiologic features of a viral gastroenteritis in infants and children

We studied 27 infants admitted to the hospital with acute diarrhea caused by human rotavirus (HRV) and obtained additional data on fecal excretion from ten outpatients with the same infection. The disease was characterized by watery diarrhea with fever and vomiting at the onset, isotonic dehydration, compensated metabolic acidosis, and increased concentrations of sodium and chloride but low concentrations of sugar in stools. Diarrhea usually ceased in three to four days when oral feedings were reduced or stopped but recurred mildly in four patients. Of 57 household contacts, 12 were symptomatic, 6 had HRV in their stools, and 19 had significantly increased serum HRV antibody titers. These features of the disease accord with available information on the pathogenesis of HRV infection. Knowledge of the clinical pattern of this newly diagnosable infection should help physicians to recognize and treat quickly this highly infectious, potentially dangerous illness.

Activities of various 4-aminoquinolines against infections with chloroquine-resistant strains of Plasmodium falciparum

The studies reported here stemmed from a personal report by Geiman on the capacity of the 4-aminoquinoline amodiaquin to inhibit in vitro maturation of ring stages of the chloroquine-resistant Monterey strain of Plasmodium falciparum. This observation, confirmed in owl monkeys infected with this strain, led to a comparison of the activities of chloroquine, amodiaquin, amopyroquin, and dichlorquinazine (12,278 RP) against infections with various chloroquine-susceptible and chloroquine-resistant strains. The results showed that: (i) these 4-aminoquinolines were essentially equally active against infections with chloroquine-susceptible strains and (ii) the activities of amodiaquin, amopyroquin, and dichlorquinazine were reduced significantly in the face of chloroquine resistance, but (iii) well-tolerated doses of these compounds would cure infections with strains that fully resisted treatment with maximally tolerated doses of chloroquine. Two other 4-aminoquinolines, SN-8137 and SN-9584, which also exhibited activity against chloroquine-resistant parasites in vitro, displayed curative activity in monkeys infected with a chloroquine-resistant strain. These observations show that there is cross-resistance among the 4-aminoquinolines, confirming earlier findings, but indicate that the dimensions of this phenomenon are sufficiently limited so that some derivatives are therapeutically effective against infections refractory to maximally tolerated doses of chloroquine.

Acid-base balance and plasma composition in the aestivating lungfish (Protopterus)

Upon entering into aestivation, Protopterus aethiopicus develops a respiratory acidosis. A slow compensatory increase in plasma bicarbonate suffices only to partially restore arterial pH toward normal. The cessation of water intake from the start of aestivation results in hemoconcentration and marked oliguria. The concentrations of most plasma constituents continue to increase progressively, and the electrolyte ratios change. The increase in urea concentration is disproportionately high for the degree of dehydration and constitutes an increasing fraction of total plasma osmolality. Acid-base and electrolyte balance do not reach a new equilibrium within 1 yr in the cocoon.

Inhibition of ent-Kaurene Oxidation and Growth by alpha-Cyclopropyl-alpha-(p-methoxyphenyl)-5-pyrimidine Methyl Alcohol

Growth of Alaska peas (Pisum sativum) is inhibited more than 60% by alpha-cyclopropyl-alpha-(p-methoxyphenyl)-5-pyrimidine methyl alcohol (ancymidol) treatment. This growth inhibition can be reversed completely by gibberellic acid application. Cell-free enzyme preparations from pea shoot tips and wild cucumber (Marah oreganus) endosperm were used to test the effects of this substituted pyrimidine on the incorporation of mevalonic acid-(14)C into ent-kaurene and ent-kaurenol, respectively. Ancyidol (10(-6)m) completely blocks the conversion of ent-kaurene to ent-kaurenol. This result was confirmed with the wild cucumber endosperm system by testing the direct conversion of labeled ent-kaurene to ent-kaurenol. Ancymidol at higher concentrations (10(-3)m) inhibits the incorporation of mevalonic acid-(14)C into ent-kaurene to a lesser extent. It is concluded that one mode of action of this growth regulator is the inhibition of gibberellin biosynthesis.

Subacute sclerosing panencephalitis measles virus: study of biological markers

Comparative studies between two measles virus strains isolated from patients with subacute sclerosing panencephalitis (SSPE) and a prototype low tissue culture passage Edmonston measles virus are described. Differences were noted in several properties. The findings described in this report suggest that strains of measles virus associated with SSPE have different biological properties and apparently cannot be distinguished from laboratory and field strains of the virus.