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Biomedical subjects

M H Maxwell

Publications and source records attributed to M H Maxwell.

At least 91 records · Page 5Linked to original sources
PubMed1982

Experimental eosinophilia in domestic fowls and ducks following horse serum stimulation.

Multiple intraperitoneal injections of horse serum given to domestic fowls at five different ages resulted in eosinophilia in 55% of adults and in 36% of the younger birds, the highest individual eosinophil level reached being 50% of the differential white cell count. The primary eosinophilic response in fowls was between injections 7 and 36 and there was a secondary response between injections 32 and 72. Horse serum injections produced an eosinophilia in 88% of adult ducks with a maximum individual level of 31% of the differential white cell count. In ducks, primary and secondary eosinophilic responses occurred at injections 13 and 28 respectively.

Age Factors↗
PubMed1981

Clinical course of patients with scleroderma renal crisis treated with captopril.

Since it has been suggested that the renin-angiotensin axis may play an important role in the severe hypertension and in the acute renal deterioration in scleroderma, we sought to determine the effectiveness of angiotensin blockade in the treatment of this disorder. Captopril controlled blood pressure successfully and easily in 4 consecutive patients with scleroderma renal crisis. Mean serum creatinine was 3.5 mg/dl after scleroderma renal crisis immediately prior to captopril. The first patient required maintenance hemodialysis because of progression to advanced renal failure before captopril was available. However, in this patient oliguric renal failure was changed to nonoliguric renal failure immediately after beginning therapy. Serum creatine stabilized in the other 3 patients. Serum creatinine peaked at 4.7 mg/dl, but then progressively improved to 3.5 mg/dl 12 weeks after captopril was begun. None of the other 3 patients required any form of dialysis during the scleroderma renal crises. Mean survival of these 4 patients was significantly greater than that of the 9 previous patients with scleroderma crisis. These observations confirm that angiotensin blockade with captopril is effective therapy to prevent renal deterioration, to control blood pressure and prolong survival in scleroderma patients with renal crisis.

Acute Kidney Injury↗
PubMed1981

The effect of weight loss on reproductive hormones in obese men.

The effects of weight reduction on reproductive hormones were investigated in 24 moderately obese men, 18-108% above ideal body weight. Serum estrone (E1), estradiol (E2), testosterone (T), percent free T (%FT), sex hormone binding globulin (SHBG) capacity, and, in 9 subjects, androstenedione (A) were measured serially before and during an outpatient supplemented fasting program (320 kcal/day) for 8-20 weeks. In the baseline state mean E1 was elevated to 100 +/- 7 pg/ml (normal, 30-60 pg/ml). The E2 was slightly elevated to 36 +/- 3 pg/ml (normal, 8-35 pg/ml). The mean T of 400 +/- 20 ng/dl was at the lower end of normal (400-1000 ng/dl). The mean %FT was elevated to 4.1 +/- 0.2% (normal 1.6-3%). The calculated free T was normal. The mean SHBG binding capacity was 0.99 +/- 0.05 micrograms dihydrotestosterone bound/dl (normal, 1.0-1.8 micrograms/dl). The mean A of 52 +/- 5.8 ng/dl was normal. These data were in accord with previous findings in much heavier men. Eight weeks of weight loss (mean, 19.5 kg) were associated with normalization of all the measured parameters. The mean E1 decreased to 48 +/- 23 pg/ml, E2 to 28 +/- 2.1 pg/ml. T increased to 536 +/- 35 pg/dl and %FT fell to 3.2 +/- 0.2%. Data on men remaining on the program for 16 or 20 weeks showed a continued fall of estrogens and stabilization of T and %FT. SHBG and A did not change significantly over the entire time period. In conclusion, increased circulating estrogens and reduced androgen binding were found in moderately obese men, which were completely corrected with weight loss.

Adult↗
PubMed1981

Leucocyte diurnal rhythms in normal and pinealectomised juvenile female fowls.

Peripheral blood from a group of control and pinealectomised juvenile female fowls was examined to establish which leucocytes manifested a diurnal rhythm and what effect pinealectomy had on these cells. The results showed that significant diurnal rhythms were displayed by the heterophils, lymphocytes and monocytes (P less than 0.001) but not by the eosinophils or basophils. Comparisons made between the control and pinealectomised birds revealed that the heterophil (P less than 0.01) and monocyte (P less than 0.1) counts were higher in the operated birds whereas the lymphocytes were lower (P less than 0.1). The eosinophils and basophils were unaffected. The removal of the pineal gland did not alter the normal diurnal rhythm of the cells.

Animals↗
PubMed1981

Production of Heinz body anaemia in the domestic fowl after ingestion of dimethyl disulphide: a haematological and ultrastructural study.

Dimethyl disulphide, a breakdown product of the amino acid S-methylcysteine sulphoxide present in high concentrations in the Brassica family, was fed to a group of adult fowls and the effects were studied haematologically and ultrastructurally. By the seventh day of the experiment Heinz bodies had appeared in most of the red blood cells and between the eighth and 12th days the birds showed leg weakness, feather ruffling and lethargy. The Heinz bodies were divided into two different morphological forms and many vacuoles were also present in these cells. The haemoglobin levels and packed cell volumes were significantly lower that those of the controls and in turn the mean cell haemoglobin and especially the mean cell haemoglobin concentration values were reduced.

Anemia, Hemolytic↗
PubMed1980

Use of saralasin to detect renovascular hypertension in childhood.

Current methods to evaluate renovascular hypertension in the pediatric population often requires a general anesthetic. Saralasin, an angiotensin II competitive inhibitor, is a safe, noninvasive technique which can be utilized at the bedside in a salt-depleted child off antihypertensive medication. Two illustrative cases are presented.

Aldosterone↗
PubMed1980

The diagnostic and therapeutic uses of saralasin in renal transplant hypertension.

Saralasin was used as a functional test of the renin-angiotensin axis in 4 renal transplant patients with hypertension. Blood pressure was recorded by an automatic recording device and plasma renin activity was measured by radioimmunoassay of angiotensin I. A positive saralasin test suggested renin-mediated hypertension despite normal peripheral renin levels in a 40-year-old man whose original kidney disease was nephrosclerosis. Since the blood pressure was refractory to intravenous sodium nitroprusside saralasin was used for 14 hours to control blood pressure before and after arteriography in the patient. Removal of the native kidneys markedly ameliorated the hypertension. A 35-year-old woman with transplant hypertension was responsive to angiotensin blockade only during a period of abrupt worsening of blood pressure associated with an acute rejection episode. Finally, 2 patients with advanced chronic rejection responded to saralasin administration. These studies confirm that 1) angiotensin blockade is a useful tool in the diagnosis of renin-dependent hypertension even when plasma renin levels are not elevated, 2) saralasin can be used to control renin-dependent forms of hypertension that are refractory to intravenous sodium nitroprusside therapy and 3) transplant hypertension associated with acute and chronic rejection appears to be renin-dependent.

Adult↗
PubMed1980

Effects of variations in sodium intake on the acute vasodepressor response to kininase II inhibition in rats with mild two-kidney, one-clip hypertension.

1. Unilateral renal artery constriction in rats maintained on a sodium-deplete, but not sodium-replete, diet induced an augmented acute vasodepressor response to kininase II inhibition produced by an intravenous injection of the dipeptidyl carboxypeptidase inhibitor captopril (250 microgram) during continuous saralasin-induced angiotensin II blockade (10 microgram/min). Dietary sodium restriction alone in sham-operated rats had no effect. 2. Acute bilateral adrenalectomy (18-24 h) did not preclude the demonstration of an augmented response to kininase II inhibition in sodium-depleted rats with benign two-kidney, one-clip hypertension. Neither did chronic administration of deoxycorticosterone acetate in intact rats elicit an augmented response. 3. The augmented acute vasodepressor response to kininase II inhibition in sodium-depleted rats with benign two-kidney, one-clip hypertension is probably due to bradykinin potentiation and secondary to an increased activity of the kallikrein-kinin system. The mechanism responsible for this apparent increase is not known, but neither hyperangiotensinemia nor hyperaldosteronism seems to play a role.

Adrenalectomy↗
PubMed1980

Hypertension associated with hyperparathyroidism is not responsive to angiotensin blockade.

Patients with primary hyperparathyroidism are frequently hypertensive. Studies were performed to determine whether the hypertension in this disorder could be corrected by saralasin infusion. Five patients with primary hyperparathyroidism and one patient with secondary hyperparathyroidism were salt depleted before saralasin testing by the administration of 1 mg/kg furosemide at 1700 h on the evening before testing. Blood pressure was measured every 2 min by an automatic recording device. Saralasin was given as a continuous iv infusion of 1, 3, 6, and 10 micrograms/kg . min for 30 min. Blood for measurement of PRA was drawn 4 min before, immediately before, and 4, 8, 12, 16, 22, 30, 60, and 90 min after the infusion was begun. Saralasin did not reduce blood pressure in these patients. The mean postsaralasin blood pressure (12--20 min after the start of the infusion) was 155/102 mm Hg compared to the control blood pressure of 156/101 mm Hg (blood pressure at -4 and 0 min). The inability of saralasin to effect a vasodepressor response was unexpected, since the mean PRA before saralasin infusion was elevated at 1895 ng/dl . 3 h (normal range, 409--818 ng/dl . 3 hr; 95% confidence limits). These studies suggest that the hypertension associated with hyperparathyroidism is not renin dependent.

Adult↗
PubMed1980

Attempted induction of an avian eosinophilia using various agents.

A series of experiments is described in which attempts were made to produce an avian eosinophilia using various agents. Although none of the experiments was decisive, two demonstrated a slight rise in the eosinophil counts. In one experiment horse serum was injected into a group of fowls on alternate days for 42 days. No eosinophils were seen in any blood smears after this treatment. After a rest period of eight days the birds received further injections for 10 days. The mean eosinophil count rose to over 4 per cent with a range of 1 to 11 per cent. It is considered that this type of response was due to a mild eosinophilia following an eosinopenia. In another experiment a group of fowls were passively immunised with material from a spontaneously occurring eosinophilic bird. Half the birds were placed in cages previously occupied by birds with high eosinophil counts. The other half was housed in another bird room. The results showed that the first group of birds consistently had more than twice the number of circulating eosinophils (3.4 per cent) compared with those of the second group (1.6 per cent). Since this increase appeared to be unrelated to the treatment other causal factors must be considered.

Animals↗
PubMed1979

The nature of virus-like particles in the paraxial muscles of idiopathic scoliosis.

Virus-like particles (VLP) have been identified by electronmicroscopy in the skeletal muscles (paraxials) of six cases of idiopathic scoliosis. These particles closely resembled VLP reported in the skeletal muscles in other conditions, e.g. Reye's syndrome, polymyositis, malignant hyperthermia, and chronic myopathy. We have shown by specific staining that these structures are composed of glycogen in a crystalline form. Using Coxsackie B infected tissue culture cells as a control we have shown that these viruses, which are of similar shape and size to the VLP, were unstained using this specific staining method.

Adolescent↗
PubMed1979

The kallikrein-kinin system in blood pressure homeostasis.

1. The acute effects of the kallikrein inhibitor aprotinin (498 ki.u./min), and the kininase II inhibitor SQ 14,225 (250 MICROGRAM), GIVEN INTRAVEnously during saralasin-induced angiotensin blockade, were studied in conscious sham-operated rats and rats with benign and malignant two-kidney, one-clip Goldblatt hypertension during dietary sodium restriction. 2. The blood pressure of conscious sham-operated rats increased significantly in response to aprotinin. It remained unchanged after SQ 14,225 in contrast to the significant vasodepressor effect seen when SQ 14,225 was given to the same rats under surgical stress and pentobarbital anaesthesia. 3. Benignly hypertensive rats showed a consistent vasopressor response to aprotinin and a marked vasodepressor response to SQ 14,225. The effects of both inhibitors were markedly and significantly blunted in malignantly hypertensive rats. 4. Our demonstration that two agents with known opposite actions on the kallikrein-kinin system produced predictable and opposite effects on blood pressure may indicate that this system is involved in the homeostatic regulation of blood pressure. It may play an important antihypertensive role in benign two-kidney, one-clip Goldblatt hypertension, a role which might be impaired in malignant hypertension.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1979

Applications of the Redy sorbent system to hemodialysis and peritoneal dialysis.

The application of sorbent technology to the treatment of uremia has been limited by the inability to adsorb urea adequately. Conversion of urea to ammonium carbonate and adsorption by zirconium phosphate provides a practical means of removing urea. This combination, together with hydrated zirconium oxide and carbon, removes uremic waste products from dialysate. Over 1500 patients are undergoing maintenance hemodialysis with this system. The dialysate composition can be modified for the treatment of patients with acute renal failure. This sorbent system is now being used for the regeneration of peritoneal dialysate. Twenty patients have undergone a total of 90 dialyses, each of 4 to 24 hours duration. One home patient has been solely on this system for two months. The application of sorbent technology to peritoneal dialysis may be the most promising approach to a wearable dialysis system.

Adsorption↗
PubMed1979

The structure of the Harderian and lacrimal gland ducts of the turkey, fowl and duck. A light microscope study.

The secretory ducts of the Harderian and lacrimal glands of the turkey, fowl and duck are similar in both structure and function. The single duct of each gland is lined by mucus-secreting epithelium. The epithelial cells vary from cuboidal to columnar, and goblet cells of three types are found. Type A, the most numerous, contain neutral mucopolysaccharides, type B have mixed acid and sulphated mucosubstances and type C, the least numerous, contain acid mucins. In both ducts glycogen is present in the lumen, but it occurs intracellularly only in the fowl up to seven days after hatching. Lymphocytes, either as diffuse tissue or as germinal centres, are found scattered along the length of the ducts. Some plasma cells and plasmablasts are also present.

Animals↗
PubMed1979

The ultrastructure of the epithelium of the ducts of the Harderian and lacrimal glands of the turkey, fowl and duck.

The ultrastructure of the epithelium in the Harderian and lacrimal gland ducts of the turkey, fowl and duck has been investigated. The findings establish that the ducts are fundamentally similar in morphology, although species differences occur. The duct epithelia are composed of cuboidal, columnar or pseudostratisfied columnar cells with many secretory vesicles as well as goblet cells. PAS-positive fibrillary rods and crystalline inclusions occupied the cisternae of the rough endoplasmic reticulum of the epithelial cells of turkeys. The crystals, which were thought to evolve from the rods, had a mean periodicity of 7.0 nm. In chicks between 1 and 3 days of age, but not in poults and ducklings, the duct epithelia displayed large intracytoplasmic deposits of glycogen which disappeared by the seventh day.

Animals↗