Intestinal calcium transport in the spontaneously hypertensive rat: response to calcium depletion

We previously found intestinal Ca2+ transport to be lower in the spontaneously hypertensive (SH) as compared with the Wistar-Kyoto control (WKY) rat. These animals were fed a relatively high (1%) Ca2+ diet, and the concentration of 1 alpha,25-dihydroxycholecalciferol [1 alpha,25(OH)2D3] in serum was the same in both groups. In the present experiment we tested the possibility that the lower Ca2+ transport in the SH rat was the result of unresponsiveness to 1 alpha,25(OH)2D3. We fed diets high and low in Ca2+ and measured serum 1 alpha,25(OH)2D3 and Ca2+ transport. Serum 1 alpha,25(OH)2D3 increased in response to Ca2+ depletion at both 5 and 12 wk in both the WKY and SH rat. With high-Ca2+ diet, Ca2+ transport was lower in SH than in WKY when studied 1) in vitro in duodenum at 5 wk of age, and 2) in vivo in proximal and distal small intestine at 12 wk of age. Ca2+ transport increased in SH in response to Ca2+ depletion, but not in WKY, except in distal small intestine in vivo at 12 wk. In summary, although Ca2+ transport is lower in the SH as compared with the WKY rat when vitamin D activity is basal through feeding a high-Ca2+ diet, Ca2+ transport increases in the SH rat in response to the increase in 1 alpha,25(OH)2D3 produced by feeding a low-Ca2+ diet. We conclude that 1) the vitamin D-regulated component of mediated Ca2+ transport is intact in the SH rat and is unrelated to hypertension, and 2) mediated Ca2+ transport under basal conditions, i.e., nonvitamin D-regulated, differs in the SH and WKY rats and may be related to hypertension.

Measurement of alpha-glucosidase activity in serum from patients with cystic fibrosis or pancreatitis

We measured the activity of a non-lysosomal alpha-glucosidase with pH optimum near 6.0 in serum from a wide variety of patients, using the fluorogenic substrate, 4-methylumbelliferyl-alpha-D-glucopyranoside. Acutely ill patients with cystic fibrosis (CF) demonstrated significant increases in alpha-glucosidase compared with CF outpatients. The former group of CF patients experienced far more severe chronic pulmonary disease than did the latter, whereas both groups had similar degrees of gastrointestinal impairment. Patients with pancreatitis associated with trauma or complicated by severe necrosis, hemorrhage, or abscess also displayed greater increases in alpha-glucosidase than did patients with uncomplicated (edematous) pancreatitis. For CF outpatients and patients with either edematous pancreatitis or pancreatic cancer, the alpha-glucosidase activity was similar to that for the general hospital-patient population. Corresponding changes were not observed for other measured serum glycosidases (alpha-fucosidase, alpha-mannosidase, beta-glucuronidase, beta-N-acetylglucosaminidase). Measurement of serum alpha-glucosidase may be of value in assessing the clinical course in CF and in differentiating necrotizing from edematous pancreatitis.

Measurement of alpha-glucosidase activity in serum from patients with cystic fibrosis or pancreatitis

We measured the activity of a non-lysosomal alpha-glucosidase with pH optimum near 6.0 in serum from a wide variety of patients, using the fluorogenic substrate, 4-methylumbelliferyl-alpha-D-glucopyranoside. Acutely ill patients with cystic fibrosis (CF) demonstrated significant increases in alpha-glucosidase compared with CF outpatients. The former group of CF patients experienced far more severe chronic pulmonary disease than did the latter, whereas both groups had similar degrees of gastrointestinal impairment. Patients with pancreatitis associated with trauma or complicated by severe necrosis, hemorrhage, or abscess also displayed greater increases in alpha-glucosidase than did patients with uncomplicated (edematous) pancreatitis. For CF outpatients and patients with either edematous pancreatitis or pancreatic cancer, the alpha-glucosidase activity was similar to that for the general hospital-patient population. Corresponding changes were not observed for other measured serum glycosidases (alpha-fucosidase, alpha-mannosidase, beta-glucuronidase, beta-N-acetylglucosaminidase). Measurement of serum alpha-glucosidase may be of value in assessing the clinical course in CF and in differentiating necrotizing from edematous pancreatitis.

Adaptation of the duodenum and ileum of the rat to mid-gut resection: enzyme activity and trace metal status

Activities of the enzymes lactase, sucrase, maltase, alkaline phosphatase, and superoxide dismutase (SOD) were measured in mucosa of duodenum and ileum of the rat after 70% resection of mid-small intestine or sham operation (transection). We also measured the concentrations of zinc, copper, and manganese in several tissues to assess trace metal homeostasis postresection. Resection resulted in decreased specific activities of disaccharidases and alkaline phosphatase in duodenum, while specific activities remained unchanged in ileum. Specific activity of total SOD (the sum of Cu-Zn and Mn SOD) and Mn SOD was the same in duodenum after resection but was markedly increased in ileum. Tissue trace metal concentrations changed minimally. Because of postresection mucosal growth, total segmental activity of disaccharidases and alkaline phosphatase was the same in duodenum and increased in ileum of resected compared to transected rats. Segmental activity of total SOD and Mn SOD doubled in duodenum and trebled in ileum of resected as compared to transected rats. Thus, total segmental enzyme activity is maintained or increased postresection by increased enterocyte proliferation rate and mucosal growth.

Calcium uptake by intestinal brush border membrane vesicles. Comparison with in vivo calcium transport

In prior studies, we examined kinetics of steady state in vivo transepithelial calcium transport in rat and hamster. The present studies related calcium uptake by the brush border to in vivo transport. We measured calcium uptake by brush border membrane vesicles from the two species. In the rat, our prior in vivo studies had shown that (a) calcium transport was mediated, (b) no nonmediated component was detectable, and (c) Vmax was 2.5 times greater in proximal than distal small intestine. In brush border membrane vesicles from the rat, Vmax for the saturable component of calcium uptake was again 2.5 times greater in proximal than distal intestine. Contrasting with in vivo studies, a major nonsaturable component was present in vesicles from proximal and distal small intestine. In the hamster, our previous in vivo studies had shown (1) both mediated and nonmediated components of calcium transport, (2) greater nonmediated transport in proximal than distal small intestines, and (3) Vmax for calcium transport twice as great in distal as in proximal small intestine. In the present study with brush border membrane vesicles from hamster, Vmax for saturable calcium transport was again twice as great in distal as in proximal small intestine. However, nonsaturable calcium transport rates relative to saturable rates were much greater with vesicles than in in vivo studies, and were greater in vesicles from distal than proximal small intestine. Since rates of saturable calcium uptake by brush border membrane vesicles parallel corresponding in vivo mediated transport rates, we conclude that the segmental rates of calcium transport in rat and hamster could be determined by brush border function.

Brain biopsy in cases of neonatal herpes simplex encephalitis

Neonatal herpes simplex encephalitis (HSE) can represent a difficult diagnostic problem when it occurs without concomitant mucocutaneus lesions and usually requires brain biopsy for diagnosis. Asymptomatic for the initial 2 to 4 weeks of life, the three infants we describe with localized HSE came to medical attention only because they developed persistent seizures and other nonspecific symptoms. Lumbar spinal fluid obtained from these children at clinical presentation showed an encephalitic pattern. Radionuclide brain scans revealed focal uptake of isotope in a variety of cortical areas, and electroencephalograms (EEGs) demonstrated repetitive, high amplitude, polyphasic sharp waves arising from analogous regions. Computed tomography (CT) showed nonspecific ill-defined areas of low density or contrast enhancement that did not correlate well with radionuclide, EEG, or clinical findings in two neonates. No infant had predominant temporal lobe involvement. Because these data suggested a multifocal, encephalitic process, all three infants underwent brain biopsy. A widespread infiltration of leukocytes and macrophages was observed in each specimen, and abundant intranuclear inclusions were present. Electron microscopy revealed abundant herpesvirus particles, and herpes simplex virus (HSV) was subsequently isolated from each sample. From our observations and our review of the literature, we propose the following criteria as indications for brain biopsy: Brain biopsy is warranted to rule out HSE when a neonate presents with seizures, cerebrospinal fluid mononuclear pleocytosis with a negative gram stain, and focal, cortical disease on EEG and radionuclide scan.(ABSTRACT TRUNCATED AT 250 WORDS)

Fatal panniculitis

The Weber-Christian syndrome (relapsing nodular panniculitis) displays a clinical spectrum varying from short, self-limited, or intermittent disease episodes to persistent disease with fatal outcome. Inflamed adipose tissue is exclusively subcutaneous in some patients and is both subcutaneous and perivisceral in others. Inflammation of fat may induce a focal cutaneous or a systemic extracutaneous histiocytic proliferative response in which hemophagocytosis may be a frequent characteristic. Major causes of death--sepsis, hepatic failure, hemorrhage, and thrombosis--are identical in the patients with and without the systemic histiocytic proliferation. Inflammation in fat, of and by itself, may be associated with significant morbidity and mortality, regardless of specific histopathology or inciting factors.

Neonatal purpura fulminans: a genetic disorder related to the absence of protein C in blood

To confirm the pathogenesis and the genetic background of neonatal-onset purpura fulminans, two unrelated infants with this rare thrombotic syndrome and 47 of their asymptomatic relatives were studied. In both families, 27 subjects with hereditary partial deficiency of protein C, including both parents of each patient, were identified. The patient in whom it was possible to evaluate protein C directly showed no detectable levels of this plasma component. These findings confirm the linkage of neonatal purpura fulminans to a genetic trait with established mendelian transmission and strongly suggest that the syndrome is an expression of homozygosity for protein C deficiency. The dramatic clinical picture and the type of pathologic change that develops as a result of the lack of circulating protein C emphasize the vital role of this protein in protection from thrombin generation, mainly within the microvascular system. However, our data do not contribute to the evidence that partial familial protein C deficiency is associated with a major risk of venous thromboembolism.

Diabetes and renal calcium binding protein in the rat

Renal calcium binding protein (CaBP), a vitamin D-dependent protein of 28,000 Mr, may be involved in calcium transport by cells of the renal tubule. The streptozotocin-diabetic rat is hypercalciuric and shows markedly decreased concentration of 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] in serum and of CaBP in small intestine. To examine the relationship of renal CaBP in diabetes to 1,25-(OH)2D3 and urinary calcium excretion, renal CaBP, serum 1,25-(OH)2D3, and urinary calcium were measured in control, diabetic, and insulin-treated diabetic rats. Treatment of the diabetic rat with insulin decreased urinary calcium excretion and elevated 1,25-(OH)2D3 toward normal. Renal CaBP was found to be the same in controls and diabetics despite a tenfold difference in concentration of 1,25-(OH)2D3 in serum, and to be unaffected by insulin treatment, which elevated 1,25-(OH)2D3 by a factor of 7 above untreated diabetics. It is concluded that in the diabetic rat either (1) the threshold concentration of 1,25-(OH)2D3 for inducing synthesis of renal CaBP is set at a much lower level than that for intestinal CaBP, or (2) since both 1,25-(OH)2D3 and renal CaBP are produced in the kidney, 1,25-(OH)2D3 exerts a paracrine effect on renal CaBP production because of its high local concentration. The increased urinary calcium excretion in the untreated streptozotocin-diabetic rat is not secondary to an alteration in renal CaBP.

Swyer-James syndrome--unilateral hyperlucent lung syndrome. A case report and review

Swyer-James syndrome is a pulmonary condition acquired following bronchiolitis obliterans early in life. Clinically characterized by repeated bouts of pulmonary infections, Swyer-James syndrome is characterized radiographically by a unilateral small, hyperlucent lung that demonstrates diminished arterial supply to the involved lung, air-trapping, and bronchiectasis. Radioimaging procedures may reveal otherwise unsuspected bilateral involvement. A 14-year-old Caucasian female with classic findings of Swyer-James syndrome is presented. The differential diagnosis of conditions that may present with a unilateral hyperlucent lung is discussed. Therapy is aimed primarily at control of the intercurrent episodes of bacterial pneumonia.

Calcium and sodium transport and vitamin D metabolism in the spontaneously hypertensive rat

Serum ionized calcium levels are lower and immunoreactive parathyroid hormone levels are higher in the spontaneously hypertensive (SH) rat than in the normotensive Wistar-Kyoto (WKy) control. We postulated that there is either a defect in the regulation of vitamin D metabolism by parathyroid hormone or that the gut target organ for vitamin D in the SH rat is unresponsive. To test these hypotheses we measured serum concentrations of vitamin D metabolites and intestinal transport of calcium and sodium. Compared with that of WKy controls, in vitro calcium transport by duodenal sacs of the SH rat was decreased (P less than 0.001) at 5 wk, before the development of hypertension, and at 12 wk, after hypertension was well established. When measured in vivo in the most proximal 20 cm of small intestine, maximum velocity (Vmax) for calcium transport was decreased (P less than 0.05) and net absorption of sodium and water was increased (P less than 0.05) in SH rats as compared with WKy rats. Vmax for calcium transport was also decreased (P less than 0.05) in the most distal 20 cm of small intestine of SH rats, but net sodium and water transport were the same in SH and WKy rats. At 12 wk, serum concentration of 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] was the same in both SH and WKy groups, but its precursor, 25-hydroxycholecalciferol, was increased (P less than 0.05) in the SH rat. We conclude that in the SH rat: (a) the concentration of 1,25-(OH)2D3 is inappropriately low in relation to the elevated immunoreactive parathyroid hormone and the depressed calcium absorption, suggesting a defect in the regulation of vitamin D metabolism; and (b) the depressed calcium absorption, in the setting of normal concentrations of [1,25-(OH)2D3], demonstrates unresponsiveness of the gut to vitamin D and may explain in part the low serum ionized calcium found in earlier studies. The presence of these abnormalities before we found a significant difference in blood pressure suggests that they may be causal, not secondary, to the hypertension.

Gentamicin and tobramycin pharmacokinetics in patients with cystic fibrosis

Pharmacokinetic variables were compared in patients with cystic fibrosis receiving gentamicin or tobramycin for the treatment of a pseudomonas pulmonary infection. Sixty-nine pediatric patients receiving gentamicin sulfate (n = 31) or tobramycin sulfate (n = 38) were studied. Doses were administered every six hours. All patients received concurrent ticarcillin therapy, had a mild fever, and normal hematocrit and serum creatinine values. Amino-glycoside pharmacokinetic variables were calculated. Tobramycin and gentamicin serum concentrations were determined by radioimmunoassay. The mean (+/- S.D.) half-lives for the tobramycin and gentamicin patients were 1.2 +/- 0.5 and 1.4 +/- 0.4 hr, respectively. The average volume of distribution and clearance values for the tobramycin and gentamicin patients were 0.33 +/- 0.20 liters/kg and 2.98 +/- 0.80 ml/min/kg, and 0.35 +/- 0.15 liters/kg and 2.79 +/- 0.75 ml/min/kg, respectively. There were no significant differences between the kinetic variables in the patients receiving gentamicin or tobramycin. To achieve steady-state peak concentrations between 7 and 9 micrograms/ml and trough concentrations below 2 micrograms/ml, gentamicin patients required 10.3 +/- 3.2 mg/kg/day and tobramycin patients required 11.1 +/- 3.9 mg/kg/day. Because of the large amount of interpatient variability in maintenance dosage requirements, therapy should be initiated with 2.5 mg/kg of gentamicin or tobramycin given every six hours and then individualized on the basis of serum concentrations and clinical response.

Elevated intestinal disaccharidase activity in the streptozotocin-diabetic rat is independent of enteral feeding

Specific and total activities of the disaccharidases, sucrase, maltase, and lactase are increased in mucosa of the small intestine of the streptozotocin diabetic rat. Because disaccharidases are essential for terminal digestion of carbohydrate, and disaccharidase deficiency is a common clinical problem, understanding the mechanisms regulating disaccharidase activity is important. In normal animals, disaccharidase activities are determined by route of feeding and are decreased by parenteral feeding. The indirect exocrine, endocrine, neurocrine, and paracrine functions of the gastrointestinal tract that are dependent on feeding via the gut are greatly decreased in parenteral as compared with enteral feeding. Hormone secretion by the gut and the pattern of response after feeding may be abnormal in diabetes and might be regulatory for disaccharidases. We tested the hypothesis that the elevated intestinal disaccharidases in diabetes are dependent on enteral feeding. Streptozotocin-injected rats (diabetics) and vehicle-injected rats (controls) were fed rat chow ad libitum for 4 days. A subset of control and diabetic animals was then killed to determine disaccharidase activity of the jejunum at the start of pair-feeding the elemental diet. The remaining animals were fed 60 cal/day of glucose, amino acid (Travasol), and electrolyte solution either intragastrically or intravenously for 4 days. Specific and total activities of disaccharidases were greater in diabetics than in controls under all feeding conditions. In controls, the pattern of activity of disaccharidase specific activity was initial greater than intragastric greater than intravenous. In diabetics, disaccharidase specific activities did not differ among groups. In both controls and diabetics, mean mucosal mass was highest initially; intermediate with intragastric feeding; and lowest with intravenous feeding. In both controls and diabetics, total disaccharidases decreased from initial to intragastric to intravenous. We conclude: (1) disaccharidase specific activity in controls is sensitive to feeding route and nature of diet, but is nearly independent of these factors in diabetics; (2) total disaccharidase activities respond to feeding stimuli in parallel with changes in mucosal mass in both controls and diabetics; and (3) the lack of feeding effect on the elevated specific activities of disaccharidases in diabetes suggests that this elevation is a response to the diabetic state and is independent of enteral factors such as luminal nutrition and gastrointestinal hormones.

Rat large bowel maintains calcium transport after small bowel resection

Because of the marked defect in calcium transport by the residual duodenum and ileum of the rat 10 days after 70% resection of mid-small intestine, we examined the calcium transport response by large intestine at this time. Although net cecal calcium absorption was decreased by one third in resected rats as compared with transected controls, total net cecal absorption was maintained because of the small growth response. Colonic calcium transport was the same in transected and resected groups, despite greater segment growth in the resected group. In comparison to the marked abnormality in calcium transport by the residual small intestine secondary to resection, the effect on the large intestine was minimal.

Superoxide dismutase activity in the intestine of the streptozotocin-diabetic rat

Insulin stimulates the production of superoxide and hydrogen peroxide in various tissues. Hydrogen peroxide has been proposed to be an intracellular second messenger for insulin and a moderator of cellular proliferation and differentiation. We previously found that cell proliferation is increased in small intestinal mucosa of streptozotocin-diabetic rats. The current study was undertaken to determine if superoxide dismutase (SOD), the enzyme that converts superoxide to hydrogen peroxide, is altered in the mucosa of the alimentary tract and renal cortex of the diabetic rat, and if so, whether SOD responds to insulin treatment. Total SOD and cyanide-insensitive [manganese-containing SOD (Mn SOD)] SOD were measured by the nitroblue tetrazolium inhibition assay. We studied ad libitum fed animals, where diabetics are hyperphagic and pair-fed animals, where hyperphagia is not present. Since cyclic nucleotides appear to control cell proliferation in some tissues, we also measured cAMP and cGMP in mucosa of the small intestine. In ad libitum fed animals, total SOD was depressed in the mucosa of duodenum, jejunum, and ileum, but not in the cecum or colon of the streptozotocin-diabetic rats. The level of Mn-SOD was not affected by diabetes or insulin treatment, but the cyanide-sensitive [copper- and zinc containing SOD (Cu-Zn SOD] SOD was depressed in the small intestine and colon of diabetic rats. Insulin treatment restored total and Cu-Zn SOD activity in the small intestine to normal and increased Cu-Zn SOD activity in the colon to normal. Pair-fed animals showed the same changes in the SOD activity of jejunal mucosa that were found in ad libitum fed animals. In renal cortex, diabetes did not alter total SOD, but increased Mn SOD and decreased Cu-Zn SOD. Both responses were reversed by insulin treatment. Cyclic nucleotide concentrations were not affected by diabetes. We conclude that SOD enzymes re altered in diabetes, at least in proliferating tissues. Responses are tissue specific. The mucosa of the small intestine and colon show decreased Cu-Zn SOD, the SOD of the cecum is unaffected, and the kidney shows increased Mn SOD and decreased Cu-Zn SOD. The SOD responses of diabetics are reversed by insulin treatment.

Calcium intake regulates 1,25-dihydroxy-vitamin D formation in the diabetic rat

Duodenal calcium absorption and serum 1,25-dihydroxyvitamin D [1,25-(OH)2D] concentrations are decreased and body growth is arrested in the streptozotocin-diabetic rat taking commercial chow with high (1.2-2%) calcium content. Treatment with insulin restores 1,25-(OH)2D3, calcium absorption, and body growth to normal. We hypothesized that the depressed 1,25-(OH)2D3 in diabetics is due in part to the minimal requirement for vitamin-D-mediated intestinal calcium transport under conditions of arrested growth and high calcium intake. We tested this hypothesis by comparing the response of serum 1,25-(OH)2D3 concentration to low (0.02%) and normal (0.5%) calcium diets in control and streptozotocin-diabetic rats. To evaluate response to short-term insulin treatment, serum 1,25-(OH)2D3 was measured after 12 or 36 h of treatment. Serum 1,25-(OH)2D3 concentrations in the 0.5% calcium diet groups were 175, 25, and 120 pg/ml for control, diabetic, and insulin-treated 36-h groups, respectively. Low calcium diets increased concentration to 625, 100, and 370 pg/ml for controls, diabetics, and insulin-treated 36-h groups, respectively. In conclusion, the diabetic retains the ability to respond to calcium deficiency, even in the insulin-deficient state. Low calcium intake, in addition to enhancing 1,25-(OH)2D3 formation in diabetics, also modulates the response to insulin treatment. These studies demonstrate that the regulatory factor(s) suppressing serum, 1,25-(OH)2D3 in diabetes is not simply insulin deficiency per se. Implications of these findings for diabetes are discussed.

Gastrin and growth of the alimentary tract in the streptozotocin-diabetic rat

Mucosal growth in small intestine of the streptozotocin-diabetic rat is increased; insulin treatment decreases growth toward normal. Gastrin is trophic to the alimentary tract. Therefore, we measured gastrin and growth of the alimentary tract in controls, diabetics, and insulin-treated diabetics. Mucosal growth of the small intestine increased at 10 days of diabetes and increased further by 20 days. Serum and antral gastrin did not respond to diabetes at 10 days. At 20 days, mean antral gastrin was increased in all diabetic groups, but the increase was significant only for a hyperphagic ad libitum-fed diabetic group, which also showed increased serum gastrin. Insulin treatment decreased serum gastrin but only partly reversed the increased mucosal growth in diabetics. We conclude that 1) gastrin is not the primary cause for increased small intestinal mucosal growth in diabetes, inasmuch as gastrin did not respond to diabetes at 10 days when mucosal growth was increased, and decreased serum gastrin in insulin-treated groups was associated with increased mucosal growth; and 2) diabetes appears to increase gastrin.

Intraventricular cerebrospinal fluid antibiotic concentrations in patients with intraventricular infections

The antibiotic concentration of the fluid from either lateral ventricle was determined 104 times in 37 patients through direct ventricular puncture, external ventricular drainage (EVD), or cerebrospinal fluid shunt sampling. The patients were 1 month to 12 years old. When the patients were receiving maximal intravenous antibiotic therapy alone, the concentrations for the most part were below 5 microgram/ml, whereas patients receiving an antibiotic through direct ventricular puncture, EVD, or a shunt reservoir usually had concentrations over 5 microgram/ml. However, wide variations from patient to patient were found with all forms of treatment despite similar dosages. Clustering of the concentration tended to occur in each individual patient. The authors conclude that, to obtain a high concentration of an antibiotic in the ventricular fluid, one should administer it directly into the ventricle.

The management of cerebrospinal fluid shunt infections: a clinical experience

Fifty patients with infected cerebrospinal fluid shunts were treated by one of three forms of treatment: a) Twenty-two patients had shunt removal, systemic antibiotic treatment, and either external ventricular drainage or intermittent ventricular taps for decompression and antibiotic administration. b) Seventeen patients had removal and immediate replacement of the shunt with intrashunt and systemic antibiotics. c) Eleven patients received intrashunt and systemic antibiotics without shunt removal. In the first group, antibiotics were given for a period of one week; in the second and third groups, intravenous antibiotics were administered for a minimum period of three weeks, and intraventricular antibiotics twice daily for two weeks. In all patients ventricular CSF was obtained and cultured 48 hours after cessation of antibiotic therapy, and cultures were repeated within four months after completion of therapy. Twenty-one of 22 patients in the first group as well as 11 of 13 of the second group, were successfully treated. In the third group only four of the 11 patients responded to treatment.