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Biomedical subjects

R Ho

Publications and source records attributed to R Ho.

At least 55 records · Page 3Linked to original sources
PubMed1988

Peripheral neuropathy complicating pancreatitis and major pancreatic surgery.

Four cases of a polyneuropathy associated with pancreatitis and pancreatic pseudocyst formation are reported. Electrophysiological investigation showed the peripheral neuropathy to be predominantly axonal in type. These patients were all seriously ill and many factors may have been involved in the pathogenesis of their neuropathy. They had all received parenteral nutrition and multiple drug therapy including metronidazole, and all had severe sepsis. There was evidence that insufficient vitamin replacement had been given during total parenteral nutrition. It was not possible to decide whether the polyneuropathy resulted from the summation of these factors, is similar to what has been called the polyneuropathy of the critically ill, or is a new association with pancreatic disease.

Acute Disease↗
PubMed1987

Development of brainstem and cerebellar projections to the diencephalon with notes on thalamocortical projections: studies in the North American opossum.

The North American opossum is born in a very immature state, 12 days after conception, and climbs into an external pouch where it remains attached to a nipple for an extended period of time. We have taken advantage of the opossum's embryology to study the development of brainstem and cerebellar projections to the diencephalon as well as the timing of diencephalic projections to somatosensory motor areas of neocortex. The techniques employed included immunocytochemistry for serotonin, the retrograde and orthograde transport of wheat germ agglutinin conjugated to horseradish peroxidase, and the selective impregnation of degenerating axons. Our results suggest that serotoninergic axons, presumably from the dorsal raphe and superior central nuclei, are present in the diencephalon at birth. Axons from the bulbar reticular formation, the vestibular complex, the trigeminal sensory nuclei, and the dorsal column nuclei reach at least mesencephalic (and probably diencephalic) levels by postnatal day (PND) 3, whereas those from the cerebellar nuclei may not grow into comparable levels until PND 5. The dorsal column and cerebellar nuclei innervate the ventral nuclei of the thalamus by estimated postnatal day (EPND) 17 and all of the diencephalic nuclei supplied in the adult animal by EPND 26. Diencephalic axons enter ventrolateral (face) areas of presumptive somatosensory motor cortex by PND 12, but do not reach dorsomedial (limb) regions until EPND 21. At both ages, diencephalic axons are limited to the cortical subplate and marginal zone; they do not innervate an identifiable internal granular layer until considerably later. Our results suggest that axons from the brainstem and cerebellum grow into the diencephalon early in development, but that they do not influence the cerebral cortex until relatively late. When the results of the present study are compared with those reported previously on the development of ascending spinal (Martin et al., '83) and corticofugal (Martin et al., '80; Cabana and Martin, '85b,c) projections, it appears that specific components of major somatosensory and motor circuits develop according to different timetables.

Animals↗
PubMed1985

Tamoxifen alone or in combination with estradiol-17 beta inhibits the growth and malignant transformation of hepatic hyperplastic nodules.

Hepatic hyperplastic nodules (HHNs) induced by the 'resistant hepatocyte method' of Solt et al. were studied as an experimental prototype of oral contraceptive-related tumors. Cytoplasmic estrogen receptors were present in all HHNs harvested and their concentration was always less than that in normal liver. No specific cytoplasmic progestin receptors could be measured in the above tumor or liver specimens. The long-term administration of estradiol-17 beta (4.8-24.0 micrograms/day) resulted in the death of all but one of 20 animals prior to termination at 10 months. Tamoxifen (0.25-2.5 mg biweekly), which did not lead to excess mortality, decreased HHN grade (proportion of liver slice occupied by HHN) and inhibited malignant transformation. Combination therapy with single-dose estradiol-17 beta (4.8 micrograms/day) and various doses of tamoxifen (0.25-2.5 mg biweekly) in most cases reduced mortality, HHN grade and malignant transformation. Cytoplasmic progestin receptors were absent and estrogen receptors were either undetectable or present in low concentrations in hepatic tumors harvested at the time of termination. Our results indicated that HHNs are hormone-dependent and that malignant transformation can be inhibited by tamoxifen alone or in combination with estradiol-17 beta.

Animals↗
PubMed1985

Tamoxifen alone or in combination with estradiol-17 beta inhibits the growth and malignant transformation of hepatic hyperplastic nodules.

Hepatic hyperplastic nodules (HHNs) induced by the 'resistant hepatocyte method' of Solt and Farber were studied as an experimental prototype of oral contraceptive-related tumors. Cytoplasmic estrogen receptors were present in all HHNs harvested and their concentration was always less than that in normal liver. No specific cytoplasmic progestin receptors could be measured in the above tumor or liver specimens. The long-term administration of estradiol-17 beta (4.8-24.0 micrograms/day) resulted in the death of all but one of 20 animals prior to termination at 10 months. Tamoxifen (0.25-2.5 mg biweekly) which did not lead to excess mortality, decreased HHN grade (proportion of liver slice occupied by HHN) and inhibited malignant transformation. Combination therapy with single-dose estradiol-17 beta (4.8 micrograms/day) and various doses of tamoxifen (0.25-2.5 mg biweekly) in most cases reduced mortality, HHN grade and malignant transformation. Cytoplasmic progestin receptors were absent and estrogen receptors were either undetectable or present in low concentration in hepatic tumors harvested at the time of termination. Our results indicate that HHNs are hormone-dependent and that malignant transformation can be inhibited by tamoxifen alone or in combination with estradiol-17 beta.

Animals↗
PubMed1983

Auditing antibiotic use in a teaching hospital: focus on cefoxitin.

The prevalence and nature of antibiotic misuse in a major teaching hospital was assessed by means of a quality-of-use audit. Cefoxitin was chosen for study. The use of cefoxitin increased rapidly during the study period, accounting for 17.7% ($15300) of the pharmacy's costs for cephalosporins during the first year of its availability but 47.7% ($60707) during the second year. Cefoxitin was inappropriately used for 43% of the patients receiving it during the first 2-month audit period and for 25% of those receiving it during the second audit period, 1 year later (p less than 0.01 by chi-square analysis).

Anti-Bacterial Agents↗
PubMed1983

Absorption of contrast medium during ERCP.

In order to assess systemic absorption, serum diatrizoate levels were measured in 25 patients requiring endoscopic retrograde cholangiopancreatography (ERCP). Urinary diatrizoate was measured in the urine of seven of these. In five additional patients, diatrizoate was instilled into the duodenum during endoscopy. Blood was drawn before and after completion of the procedure in all patients and at intervals from 2 to 24 hr in nine. Eighteen-hour urine collections were obtained from seven patients. Increases in serum diatrizoate concentration were 7.10 micrograms/ml +/- 3.01 (mean +/- SE) in the duodenal-instillation patients, 230.68 +/- 53.24 micrograms/ml in 9 patients in whom only the pancreatic duct was visualized, 7.83 +/- 1.05 micrograms/ml in three patients in whom only the bile duct was visualized, and 77.67 +/- 28.22 micrograms/ml in 13 patients in whom both ducts were visualized. The mean total urinary excretion of diatrizoate was 3.05 +/- 0.98 g of diatrizoate. Endoscopists performing ERCP should be aware of the likelihood of systemic absorption and the possibility of reactions to iodinated contrast materials in sensitive patients.

Absorption↗
PubMed1979

Effect of chronic alcohol use on hepatic testosterone 5-alpha-A-ring reductase in the baboon and in the human being.

Hepatic testosterone 5-alpha-A-ring reductase (HTAR) activity was measured in open liver biopsies in eight alcohol-fed baboons and eight pair-fed controls. The animals were studied after at least 1 yr of alcohol feeding. In the alcholol-fed animals, a significant fall in enzyme activity was noted. This occurred whether the enzyme levels were related to soluble protein, to DNA, or to wet tissue weight, showing that the change was due to a decrease in the specific activity of the enzyme. In addition, aspiration liver biopsy specimens were obtained from 14 men and women with alcoholic liver disease. Again, there was a significant decrease in HTAH activity in these patients compared with a normal population. No relationship was found between hepatic histology and HTAR levels in either the baboon or human population with alcoholic liver disease, suggesting that the changes in enzyme activity were related to an alcohol effect rather than to liver disease per se. This study demonstrates that chronic alcohol use decreases the function of the enzyme which controls an important rate-limiting step in the metabolism of testosterone in the liver and that this effect may be due primarily to alcohol.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1979

Low incidence of bacteremia following endoscopic retrograde cholangiopancreatography (ERCP).

Fifty patients (29 females) undergoing ERCP were studied prospectively for the occurrence of bacteremia associated with this endoscopic procedure. Each patient had blood samples drawn for aerobic and anaerobic cultures before endoscopy, after entering the duodenum, 5 and 15 minutes after cannulation of the papilla of Vater. Subcultures were made at 24 and 48 hours for a total of 1,200 cultures. No positive cultures were obtained in 48 patients. One patient developed a Staphylococcus epidermidis bacteremia during the procedure. The cleansing technic for the instruments consisted of alcohol and water only. Prophylactic antiobiotics were not administered. In contrast to other gastrointestinal procedures, our results suggest that bacteremia is an uncommon occurrence in ERCP despite the longer duration of the procedure and instrumentation of a sterile duct system.

Adult↗
PubMed1979

Abnormalities of the bile duct associated with chronic pancreatitis.

The association of abnormalities of the common bile duct with chronic inflammatory disease of the pancreas is described in this report in which the important diagnostic role of endoscopic retrograde cholangiopancreatography (ERCP) is emphasized in this disease entity. ERCP was utilized as a single diagnostic modality in 27 patients (15 females) in whom both the biliary tree and pancreatic ducts were demonstrated. Abnormalities of the pancreatic duct were noted in all patients while the associated changes of the common bile duct were noted in 12 (44%--7 females). The role of ERCP in confirming the diagnosis and its importance in planning specific therapy is emphasized.

Adult↗
PubMed1979

Treatment of Kaposi's sarcoma with bleomycin.

Two cases of Kaposi's sarcome that responded to bleomycin therapy are reported herein. The first case, resistant to various treatments, responded remarkably well after 240 mg of bleomycin was administered over a thirteen month period. The second case had rapidly progressive untreated Kaposi's sarcoma of six months's duration; a prompt response was obtained to an initial course of 105 mg of bleomycin.

Aged↗
PubMed1976

Conversion of 3T3 fibroblasts into adipose cells: triggering of differentiation by prostaglandin F2alpha and 1-methyl-3-isobutyl xanthine.

Green and Kehinde [(1974) cell 1, 113-116] have isolated clones of Swiss 3T3 fibriblasts that are able to convert to adipose cells. In this paper we report on two chemicals (prostaglandin F2alpha, 0.1 mug ml, and 1-methyl-3-isobutyl xanthine, 0.5 mM) that are able to rapidly and irreversibly program the fibroblasts to differentiate into adipose cells. Confluent cultures treated with prostaglandin F2alpha and insulin for 3-5 days, followed by insulin alone for 7-48 hr, yield numerous adipocyte colonies compared to control dishes and dishes treated with insulin alone. Cells treated with prostaglandin F2alpha or 1-methyl-3-isobutyl xanthine alone, rinsed, and then exposed to insulin gave similar results, indicating that the continuous presence of the triggering agent is not required to elicit the conversion of the fibroblasts to adipocytes. Agents that raise intracellular levels of 3':5'-cyclic AMP. 1.0 mM; 8-bromo-cyclic AMP,0.5 mM; and prostaglandin E1, 0.1 mug/ml) do not trigger the conversion process, suggesting that cyclic AMP may not be the mediator of differentiation in these cells. 8-Bromo-cyclic AMP, however, does induce thase; 3':5'-nucleotidohydrolase; EC 3.1.4.17) in these cells; the induction appears to be mediated by increases in intracellular cyclic AMP levels. These results indicate that this cell line might offer a system for studying the regulation of a type of cellular differentiation.

3',5'-Cyclic-AMP Phosphodiesterases↗