Biomedical subjects

P Ho

Publications and source records attributed to P Ho.

At least 73 records · Page 4Linked to original sources

PubMed1988

Neuroendocrine (Merkel cell) carcinoma of the vulva.

The clinical, histopathologic, and ultrastructural features of a primary cutaneous vulvar neuroendocrine neoplasm (Merkel cell carcinoma) are presented. This recently described tumor arises in the dermis and is often aggressive with metastasis to regional lymph nodes. Ultrastructural study of this case reveals morphologic similarities to normal cutaneous Merkel cells, including peripherally located dense-core neurosecondary-like granules, and immunohistochemical studies revealed ACTH within neoplastic cells. By light microscopy this tumor is readily confused with other primary or metastatic cutaneous neoplasms; therefore, the importance of electron microscopic examination is emphasized for definitive diagnosis of this unusual tumor.

Female↗

PubMed1988

[Multiple sclerosis disclosed by spinal anesthesia].

A case is reported of an acute onset of previously undiagnosed multiple sclerosis, revealed by an oculomotor paralysis following spinal anaesthesia performed for minor orthopaedic surgery. The need for a complete preoperative physical examination is underlined by this case, looking for latent neuromuscular disorders before undertaking such techniques, and for a thorough neurological work-up should such a complication arise. The harmlessness of regional anaesthesia in multiple sclerosis patients is controversial; without entering into such a debate, the direct relationship between spinal anaesthesia and acute exacerbation of the disease in our patient seemed more than likely.

Adult↗

PubMed1988

Neural stimulation of gluconeogenesis in isolated pyruvate-perfused rat kidneys.

To estimate peritubular norepinephrine concentration during renal nerve stimulation, we compared gluconeogenic responses in isolated pyruvate-perfused rat kidneys with electrical nerve stimulation and exogenous norepinephrine. During 2 and 4 Hz stimulation, venous norepinephrine was 1.7 +/- 0.4 and 2.7 +/- 0.9 nmol/L, respectively. Intra-arterial norepinephrine infusion of 60 pmol/min for 20 min (an amount corresponding to that released during 4 Hz stimulation) resulted in venous norepinephrine levels of 3.6 +/- 0.6 nmol/L. Electrical stimuli (1, 2, and 4 Hz) sustained increases in vascular resistance of 2, 5, and 11% during 20 min of stimulation, while the norepinephrine infusion increased resistance gradually by 8% and a bolus (12.5 nmol/L) transiently increased resistance by 2%. All electrical and norepinephrine interventions, except 1 Hz, decreased fractional Cl excretion. Decreased glomerular filtration rate was observed only during 4 Hz stimulation. Gluconeogenesis transiently increased during stimulation at 2 or 4 Hz (12% (p = 0.056) and 15% (p = 0.028]. The 5% increase in gluconeogenesis during norepinephrine infusion did not differ from the increase during 4 Hz stimulation (p = 0.45). An exogenous norepinephrine bolus (12.5 nmol/L) increased gluconeogenesis 60% for 15 min, four time more than the response to 4 Hz nerve stimulation (p = 0.012). Therefore, we conclude that nerve stimulation sufficient to produce sustained vasoconstriction and antinatriuresis raised norepinephrine concentration less than 12 nmol/L on the peritubular surface of the S1 proximal tubule, thus accounting for the small gluconeogenic response.

Animals↗

PubMed1988

Long term pulsatile growth hormone (GH)-releasing hormone therapy in children with GH deficiency.

We treated seven GH-deficient children with 3-hourly 1 microgram/kg sc pulses of GHRH-(1-44) for 6 months and 2 micrograms/kg.pulse for another 6 months. Four patients had a serum GH response to iv GHRH before treatment, and an additional patient responded to iv GHRH after 1 month of pulsatile sc GHRH administration. The mean cumulative growth velocity increased from a pretreatment mean of 2.7 +/- 0.2 (+/- SE) to 8.4 +/- 2.5 and 5.4 +/- 0.7 cm/yr after 2 months and 1 yr of treatment, respectively. Low dose pulsatile GHRH therapy was effective in promoting growth in five of seven children, with height gain ranging from 4.4-7.5 cm at the end of 1 yr's therapy. Only one of the two patients who did not respond to GHRH had an improvement in linear growth when they were subsequently treated with synthetic GH. The other patient, a 16.5-yr-old pubertal girl who had both satisfactory GH and somatomedin-C responses during GHRH therapy, did not respond to either GHRH or, later, synthetic GH. The pretreatment serum GH response to iv GHRH, the serum somatomedin-C concentrations, and the peak serum GH response during sc GHRH therapy were not reliable predictors of clinical response.

Adolescent↗

PubMed1987

Specific alpha 1-, alpha 2-, and beta-responses to norepinephrine in pyruvate-perfused rat kidneys.

We compared the effects of alpha- and beta-adrenergic agonists on vascular resistance, gluconeogenesis (GNG), and electrolyte excretion in pyruvate-perfused rat kidneys. Norepinephrine (NE) (15-60 nM) increased vascular resistance (2-19%) and GNG (42-49%) and decreased fractional excretion of Na (18-34%), Cl (38-48%), and K (13-27%). Prazosin and yohimbine blocked the vasoconstrictor but not the antinatriuretic response. Prazosin revealed an antiphosphaturic and inhibited the gluconeogenic response. Propranolol blocked the effect on Na and Cl (66%) and K excretion (100%). Methoxamine (0.6-1 microM) maximally increased GNG (40-52%) with little effect on vascular resistance (+0-9%) and NaCl excretion (-0-11%). Adding glucose to the perfusate increased methoxamine's effects on electrolyte excretion and vascular resistance. Mercaptopicolinate did not alter methoxamine's effects during pyruvate perfusion. Clonidine (0.1 microM) decreased phosphate excretion without vasoconstriction or antinatriuresis; 0.5-1 microM vasoconstricted and decreased NaCl excretion. Isoproterenol (0.1 microM) vasodilated and decreased Na (25%), Cl (40%), and K excretion (20%). Thus alpha 1- and beta-receptors could account for the effect of NE on GNG and K reabsorption, respectively. Synergism of alpha 1, alpha 2, and beta were required for full antinatriuresis. Glucose increased alpha 1-stimulated vasoconstriction and antinatriuresis. Blocking alpha 1-receptors revealed an alpha 2-like antiphosphaturic response.

Animals↗

PubMed1987

Alpha 1-adrenergic stimulation of renal Na reabsorption requires glucose metabolism.

The effect of glucose on renal responses to alpha 1-adrenergic stimulation was examined in isolated rat kidneys perfused with 5 mM lactate, 5 mM alanine, 0.5 mM pyruvate, and 0.2 mM mercaptopicolinic acid. Adding 5 mM glucose to this perfusate vasodilated the kidneys and raised the glomerular filtration rate (GFR) and free water clearance without altering fractional sodium excretion. alpha 1-Adrenergic actions were evaluated with norepinephrine (NE, 60 nM), methoxamine (600 nM), and prazosin (1 microM). Glucose altered neither the vasoconstriction nor the reduction in GFR produced by NE and methoxamine but increased the antinatriuretic responses (P less than 0.001). Glucose was required for prazosin to inhibit the effect of NE on sodium and lithium excretion. The nonmetabolized glucose analogue, alpha-methyl-D-glucoside (5 mM), did not increase the antinatriuretic response to NE, therefore glucose metabolism and not Na cotransport stimulated the alpha 1-adrenergic response. Glucose did not alter alpha 1-adrenoceptor number or binding affinity for prazosin in renal cortical homogenates. We conclude that glucose metabolism in the proximal tubule is involved in the stimulation of sodium reabsorption by alpha 1-adrenoceptor agonists.

Absorption↗

PubMed1987

Sorbents used for removal of urea in the system of artificial kidney.

Three copolymers were made from the suspension polymerization of methyl acrylate, divinyl benzene and triallyl isocyanurate; acrylamide and N,N'-methylene-bis-acrylamide; and styrene and divinyl benzene. These copolymers were then converted into derivatives of hydrazides through several steps. They were used as polymeric sorbents. They sorbed in situ a little bit less than 40 mg. of urea per gram of sorbent at 37 degrees C, pH = 7.0-7.4 and the percentage of urea in the buffer solution being 130 mg%. The sorption of urea was related to the specific surface area of the sorbent, temperature of sorption and time of sorption, concentration of urea, pH value of solution etc. In order to find out whether the above-prepared derivatives of hydrazide can be used clinically as polymeric sorbents in artificial kidney system, the junior author carried out experiments with patient's dialysate as imitated to hemodialysis. From the results, it indicates the sorbents might be used in artificial kidney system because they sorbed the urea from hemodialysate as much as that of the pure urea in a buffer solution.

Adsorption↗

PubMed1985

Metabolic control of renal vascular resistance and glomerulotubular balance.

Renal vascular resistance (RVR) and glomerulotubular balance were examined in isolated rat kidneys perfused at 100 mm Hg with 10 mM lactate (L) or 10 mM pyruvate (P) or 5 mM glucose (G) either alone or with a mixture of 20 amino acids (13.5 mM, AA); albumin oncotic pressure 24 +/- 1 mm Hg. RVR was L greater than P greater than G = AA. Vasodilation by G and AA was additive. Proximal tubular sodium-cotransport was evaluated from fractional reabsorption (FR) of phosphate (Pi), G, and L. FR Pi was 91% in AA, 86% in P, 72% in L, and 67% in G. Combining AA or P with L or G increased FR Pi to 89 to 90%. FRs of G and L by G and L perfused kidneys were 83 and 78%, respectively, and were increased to 97 to 99% by combining G or L with AA or P. P and AA also increased FR sodium and FR water when combined with L or G or when combined with each other. GFR correlated positively with FR sodium and FR water. AA combined synergistically with L to increase gluconeogenesis. These results indicate that, compared with pyruvate or AA, neither glucose nor lactate alone is a good energy source for proximal tubular reabsorption, that synergistic interactions between AA or pyruvate and lactate or glucose augment GFR by increasing proximal tubular reabsorption, and that the vasodilating effects of glucose and AA are not related directly to their effects on GFR.

Amino Acids↗

PubMed1985

Assessment of habitual physical activity by a seven-day recall in a community survey and controlled experiments.

Assessment of habitual physical activity in epidemiologic and health education studies has been difficult. A seven-day physical activity recall interview was developed and administered in a community health survey, a randomized clinical trial, and two worksite health promotion programs during 1979-1982. These studies were conducted in several populations in California, Texas, Pennsylvania, and New Jersey. Energy expenditure estimates from the physical activity recall conformed to expected age- and sex-specific values in the cross-sectional community survey. Estimates of energy expenditure were also congruent with other questions on physical activity and job classification. In a randomized, one-year exercise trial, the physical activity recall detected increases in energy expenditure in the treated group and was positively associated with miles run during training (p less than 0.05). Changes in energy expenditure were associated with changes in maximal oxygen uptake (VO2max (r = 0.33, p less than 0.05) and body fatness (r = -0.50, p less than 0.01) at six months, and in high density lipoprotein-cholesterol (r = 0.31, p less than 0.05) and triglyceride (r = -0.41, p less than 0.01) at one year. The physical activity recall detected significant (p less than 0.01) increases in energy expenditure in treatment groups in two worksite health promotion projects. These data suggest that the physical activity recall provides useful estimates of habitual physical activity for research in epidemiologic and health education studies.

Adolescent↗

PubMed1984

Abnormal excretion of oestrogens in complicated pregnancies.

The tremendous interpatient variations that occur for oestrogen excretion during pregnancy are largely overcome by expressing results in terms of relative concentrations (i.e., as percent of total oestrogens excreted). Specimens of urine from 28 pregnant patients with a variety of complications were assayed for their oestrogen content by an "oestrogen profile" technique and the results thus expressed were compared with those from 20 normal pregnancies. Statistically significant changes are shown in the group of patients in the "above" normal range (normal range = normal mean +/- 3 X SE) for five oestrogens (oestrone, 2-hydroxyoestrone, 2-methoxyoestrone, 2-hydroxyoestradiol, and 2-hydroxyoestriol) and "below" the normal range for one oestrogen (oestriol). When the means of the oestrogen values for the different groups of patients were examined, two things became obvious; firstly, only patients with hypertension showed these changes, and secondly, two additional oestrogens (16-hydroxyoestrone and 16-epioestriol) were excreted in large amounts by the normotensive "high risk" patients. A comparison of the two methods of expressing oestrogen assay results is made quantitatively (as milligrams per day) versus relatively (as percent of total oestrogens excreted), and advantages and disadvantages of each are discussed.

Diabetes Mellitus↗

PubMed1984

Insulin autoimmunity as a cause of hypoglycemia.

"Autoimmune" hypoglycemia is a syndrome consisting of fasting hypoglycemia, hyperinsulinemia, and insulin-binding antibodies in a patient who has never been exposed to exogenous insulin. The stimulus for insulin-antibody formation and the mechanism of the hypoglycemia in this condition remain unknown. Three patients with this rare syndrome had severe hypoglycemia of limited duration. Two had received a drug containing a sulfhydryl group (methimazole and penicillamine) as treatment for an autoimmune disorder (Graves' disease and rheumatoid arthritis, respectively). A third patient who underwent surgery for a suspected insulinoma was found to have pancreatic beta cell hyperplasia. Drugs containing a sulfhydryl group may have a role in the etiology of the syndrome. Additionally, our findings suggest a relationship between circulating insulin antibodies and beta cell hyperplasia.

Autoantibodies↗

PubMed1981

Acute syphilitic optic neuritis.

Two patients experienced acute unilateral visual loss as a manifestation of early infectious (secondary) neurosyphilis. In both cases, optic disc swelling was preceded by the development of a characteristic rash accompanied by mild signs of meningeal inflammation. Other signs of ocular inflammation, such as uveitis or retinal vasculitis, were absent. Optic neuritis may occur as a manifestation of the meningeal inflammation that can accompany secondary syphilis. In such patients, it is important to confirm involvement of the CNS and to institute appropriate antibiotic therapy.

Acute Disease↗

PubMed1980

Treatment of psoroptic mange with avermectins.

Good control of Psoroptes cuniculi was achieved in rabbits treated with various avermectin analogues by topical application or by subcutaneous injection of the 22,23-dihydroavermectin B1.

Administration, Topical↗

PubMed1979

Radioimmunoassay of secretin in serum.

A radioimmunoassay for the measurement of immunoreactive secretin has been developed. The assay is specific and sensitive so that 2.8 fmol/ml can be measured. Basal secretin levels in man are generally undetectable and a protein-rich meal does not elicit a secretin response. However, the intraduodenal instillation of HCl leads to a prompt rise in circulating immunoreactive secretin and exogenous secretin administered intravenously is easily and accurately measured.

Animals↗

PubMed1979

Cholecystokinin-like peptides in brain and intestine of obese-hyperglycaemic mice.

Cholecystokinin-(CCK) like peptides have been measured in the brain and small intestine of ob/ob hyperglycaemic mice and lean littermates. CCK-like peptides were measured by radioimmunoassay employing an antiserum to CCK octapeptide (CCK 8) and gastrin 17 I125 label. Although this antiserum detects gastrin with equal affinity to CCK, concomitant assay of tissue extracts with a gastrin specific antibody failed to reveal any detectable gastrin. Extracts of brain and small intestine showed levels of CCK of 96 +/- 12.6 pmol g-1 and 45 +/- 6.1 pmol g-1 in the obese mice; 101 +/- 8.7 pmol g-1 and 36 +/- 2.5 pmol g-1 in the lean mice. These were not significantly different. It has been suggested that CCK may be a satiety factor and it has been reported that there is less CCK in brain of obese mice compared with lean mice. This study has failed to confirm the previous finding and indicates that, in this animal model, tissue levels of CCK probably do not modulate appetite.

Animals↗

PubMed1979

Effects of a chemotactic factor, N-formylmethionyl peptide, on adherence, superoxide anion generation, phagocytosis, and microtubule assembly of human polymorphonuclear leukocytes.

FMLP promoted microtubule assembly in PMNs at concentrations which were chemotactic for the cells. At higher concentrations than those required for chemotaxis, FMLP enhanced the adherence of PMNs to nylon glass fibers. With colchicine, PMN adherence was inhibited, but upon exposure to FMLP, PMN adherence could be restored. The effect of FMLP on PMN adherence was transitory and was no longer evident by 5 min. At concentrations similar to those employed in the adherence studies. FMLP induced the cells to briefly generate O-2, since ferricytochrome C reduction was no longer evident by 5 min. Pretreatment of the PMNs with cytochalasin B enhanced the release of O-2 by PMNs exposed to FMLP. On the other hand, there was no effect of FMLP on phagocytosis of C3-coated particles. These results suggest that FMLP induces responsive cells to develop a hyperadherent plasma membrane which is largely independent on microtubule control. Since oligopeptides similar of AMLP are formed in bacteria, it is likely that the action of N-formylated peptides is important in regulating the inflammatory response.

Cell Adhesion↗

PubMed1978

The preparation of pregnancy urine for an estrogen profile.

A method is described for purifying the estrogen content of pregnancy urine with little loss of the labile estrogens. The procedure makes use of the initial 50-fold purification effected by their precipitation whith ammonium sulphate, with simultaneous elimination of most urinary corticosteroids and 50--60% of urinary ketosteroids. It also employs the antioxident ascorbic acid as an additive in most stages of the procedure. The mild organic-solvent-HIO partition system of Brown is used for separating the strongly polar, 2including all "labile" estrogens, and of the weakly polar estrogens, from neutral steroids. The remaining neutral steroid still interfering with the assays were removed by an ascorbic acid treated ion exchange resin (AG 1). The final residues were revealed by mass-spectroscopy to consist almost solely of estrogens. Gas-liquid chromatography in which just 2 chromatograms are required yields a total of 12 "estrogen" peaks (for 12 estrogens which are excreted in amounts greater than 0.1 mg/day) in normal pregnancy urine, including all the known labile estrogens. Identification as estrogen for all but a few minor peaks of the gas chromatogram was obtained by mass-spectroscopy. The practical significance of the method lies in the fact that some labile estrogens are much more important in the estrogen metabolism of pregnant and nonpregnant women than heretofore generally thought.

Ammonium Sulfate↗

PubMed1977

Fluidotherapy: evaluation of a new heat modality.

The development of a new heat therapy modality (fluidotherapy) consisting of a bed of solid particles suspended in air is reported. Measurements of time integrated heat absorption by a hand immersed in the fluidotherapy unit at 120F (48.9C), a whirlpool at 105.2F, and a paraffin bath at 126F show the average heat absorption to be 17.2, 5.6 and 4.8 BTU respectively during a 15-minute treatment.

Body Temperature↗