Effects of altered dietary calcium intake in experimental hypertension: role of intracellular free magnesium.

Blood pressure, ionic and hormonal effects of high (1.8%) versus low (0.2%) dietary calcium intakes were explored in uninephrectomized DOC-NaCl rats, in two-kidney, one clip (2K, 1C) Goldblatt hypertensive rats and their respective controls. High-calcium diets lowered blood pressure (P less than 0.05) in DOC-NaCl and in control uninephrectomized rats drinking 1% NaCl. However, calcium loading in renin-dependent 2K, 1C rats elevated blood pressure (P less than 0.05) but had no effect in sham-operated controls. Plasma renin activity rose in all animals, while serum ionized calcium rose significantly only in dietary salt-loaded animals. Intracellular free magnesium levels were consistently, inversely linked to blood pressure (r = -0.92, P less than 0.001). This linkage was independent of plasma renin activity, serum ionized calcium values and dietary calcium content. These results demonstrate that the same alteration in dietary mineral content can produce opposite blood pressure effects in different pathophysiological subtypes of hypertensive disease. We conclude that intracellular free magnesium levels directly participate in the final common pathway of events regulating blood pressure and vasoconstrictor tone.

The role of closed reduction in tibial shaft fractures.

Although several methods of treating difficult tibial shaft fractures have been introduced in the past few decades, closed reduction remains the cornerstone of treatment. The physician must be able to recognize those tibial fractures suitable for treatment by this method, as opposed to fractures that have the potential to cause problems and would be better handled initially by other means. Properly performed, closed reduction in conjunction with early weight bearing accomplishes the goals of solid bony union, normal function, and a cosmetically acceptable appearance. This nonoperative approach avoids the potential morbidity associated with surgery and has been shown to give excellent results in the hands of a number of different physicians.

In-shoe plantar pressure measurement of the first metatarsophalangeal joint in asymptomatic patients.

Using an in-shoe plantar pressure sensor, the pressure under the first metatarsophalangeal (MTP) joint was measured in 20 asymptomatic control subjects during their normal gait. A 7-micron in-shoe pressure sensor recorded the pressure under the first MTP joint in the 20 volunteers while they were wearing their normal footwear (athletic footwear), a wooden postoperative shoe, a fiberglass short leg walking cast, and a postoperative shoe with a first MTP joint cutout orthotic device. The results showed both casting, and the postoperative shoe with the first MTP joint cutout orthotic device significantly reduced pressure under the first MTP joint compared with normal footwear, with an average decrease of 31% and 43%, respectively. However, the standard postoperative shoe did not significantly reduce first MTP pressure compared with normal footwear. Certain surgeries performed on the distal first metatarsal may benefit from a diminution of loading forces encountered during normal gait. The results of this study indicate that a reduction of first MTP pressures can best be accomplished with either a postoperative shoe with a cutout orthotic device or a short leg walking cast. A standard postoperative shoe showed inconsistent results and had no statistically significant effect on decreasing the pressure under the first MTP joint.

Renal divalent cation excretion in secondary hypertension.

1. To determine whether abnormal renal calcium excretion is unique to primary genetic hypertension, blood pressure and 24 h urinary excretion of calcium, magnesium, sodium and creatinine were measured in deoxycorticosterone-saline and two-kidney, one-clip Goldblatt hypertensive rats and in their respective controls on low (0.2%) and high (1.8%) dietary calcium intakes. 2. Calcium supplementation lowered blood pressure (P < 0.05) in deoxycorticosterone-saline rats and in control saline-loaded rats, raised blood pressure in two-kidney, one clip rats, and had no effect in sham-operated control rats. 3. On both diets, calcium excretion was higher in hypertensive than in normotensive rats. The high calcium diet increased urinary calcium excretion in all rats, but the changes in urinary calcium excretion closely paralleled the diet-induced changes in blood pressure. Thus, urinary calcium excretion in deoxycorticosterone-saline animals, in whom calcium lowered blood pressure the most, rose the least (107%). Urinary calcium excretion rose the most in two-kidney, one-clip animals (1113%), whose blood pressure also rose the most. 4. Urinary magnesium excretion was also abnormal in hypertensive rats compared with normotensive rats, falling on the high compared with the low calcium diet in normotensive rats, but not in either hypertensive strain. Furthermore, urinary magnesium excretion was closely linked to urinary calcium excretion in saline-loaded control rats (r = 0.78; P = 0.008), but was dissociated from urinary calcium excretion in deoxycorticosterone-saline rats (r = 0.02; not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the wheezy infant.

BACKGROUND: The infant with persistent or recurrent wheezing during the first 2 years of life poses a diagnostic dilemma, which can be a source of anxiety to both physicians and parents. A suggested diagnostic approach to the causes of infantile wheezing is outlined. OBJECTIVES: 1. To review the physiologic considerations of the infant's airways that predispose to wheezing. 2. To discuss the key physical findings, family history, and risk factors associated with wheezing in infants. 3. To develop a rational approach to the differential diagnosis and management of infantile wheezing. DATA SOURCES: The MEDLINE database as well as our clinical experience pertaining to infantile wheezing. CONCLUSIONS: This review discusses the diagnostic evaluation and treatment of the wheezing infant. We suggest that infant pulmonary function testing may be used as one diagnostic aid in the workup of the wheezing infant.

Intracellular pH in human and experimental hypertension.

31P NMR spectroscopy was utilized to evaluate intracellular pH in erythrocytes from normotensive (n = 15) and from untreated (n = 16) and treated (n = 24) human essential hypertensive individuals. Intracellular erythrocyte pH was also measured in normotensive rats on different dietary calcium intakes as well as in volume-dependent deoxycorticosterone/saline and renin-dependent, 2 kidney, 1 clip (2K-1C) Goldblatt hypertensive rat models. Untreated essential hypertensives had significantly lower intracellular pH values compared with normotensive subjects [7.17 +/- 0.02 vs. 7.28 +/- 0.02 (mean +/- SEM), significance level = 0.01]. Treated hypertensives had intracellular pH values indistinguishable from normotensives [7.27 +/- 0.02 (mean +/- SEM)]. Similarly, pH values for each rat model varied inversely with blood pressure, regardless of whether increased dietary calcium intake lowered pressure (normotensive and deoxycorticosterone/saline hypertensive rats) or elevated it (2K-1C Goldblatt hypertensive rats). These results demonstrate that lower intracellular pH values are commonly observed in various hypertensive states and suggest that they may contribute to the pathophysiology of the hypertensive process. Alterations in intracellular pH may also underlie the clinically observed linkage of hypertension with other disease syndromes, such as diabetes mellitus and obesity.

Cockroach allergy in Kentucky: a comparison of inner city, suburban, and rural small town populations.

The cockroach has been reported as a major allergen in inner city asthmatic patients. The retrospective chart review of 799 patients tested over a 10-year period (1981-1991) derived from a private allergy practice and a university allergy clinic is reported. Patients from both groups were divided geographically by home zip codes into inner city, suburban, or rural small town populations. Criteria for positive skin tests were wheal greater than 5 mm for prick and greater than 10 mm for intradermal tests with flare. Overall, 36.9% (295/799) of all patients surveyed were positive by either prick or intradermal skin testing. Cockroach reactivity was observed in 38.6% (95/246) of the private patients tested with 36.2% (200/553) of the university patients showing positive results. The inner city populations in both groups of patients were similar with 43.7% and 40.3% of the private and university patients, respectively, testing positive, with an overall positivity of 41% for all inner city patients. Inner city and rural small town populations for both study groups demonstrated almost identical reactivity with 41% and 43% overall positivity, respectively. Of the suburban group, 37.5% of the private patients and 28.8% of the university patients had reactive skin tests results with an overall rate of positivity of 30.1%. This rate (30.1%) is significantly less than the rate for either inner city (41.0%, P < .05) or rural small town (43.6%, P < .01) populations.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiographic imaging studies in pediatric chronic sinusitis.

BACKGROUND: The diagnosis of chronic sinusitis is dependent on the radiographic evidence of sinus disease. METHODS: We evaluated the performance of radiographs and computed tomographic (CT) scans for the examination of the paranasal sinuses of 91 patients of both sexes, ranging in age from 2 to 17 years, who had chronic upper respiratory tract symptoms for at least 3 months. The CT scan findings were categorized as no disease; minimal disease, and mild, moderate, and severe sinusitis. RESULTS: Fifty-eight patients (63%) had chronic sinusitis: CT scan abnormalities were minimal in 17%, mild in 19%, moderate in 21%, and severe in 43%. There was a statistically significant correlation between rhinorrhea (r = 0.25, p = 0.01), cough (r = 0.27, p = 0.009), and the severity of sinus abnormality as determined by CT scan. Clinical presentation in the mild, moderate, and severe sinusitis groups (p < 0.05) was significantly different from that of the no disease group, whereas the minimal disease group had subclinical presentation (p = 0.11). Clinically significant chronic sinusitis often occurred at multiple sites: 44% of patients had pansinusitis, 50% had disease involvement of at least two sinuses, and 6% had disease in a single sinus. When sinus radiographs were compared with CT scans (n = 70 cases), radiographs could not identify minimal disease. For clinically significant sinusitis, sinus radiographs detected disease in 1 of 5 (20%) frontal sinuses, 0 of 12 (0%) sphenoidal sinuses, and 17 of 31 (54%) ethmoidal sinuses. With the minimal criteria of 40% to 50% opacification or fluid level filling of the maxillary antrum, radiographs detected disease in 37 of 49 (75%) cases. The sensitivity and specificity for a Waters view to confirm clinically significant chronic sinusitis without specifying the sites and severity were acceptable at 76% and 81%, respectively. When limited sinus CT scans were compared with full CT evaluation (n = 49 cases), limited studies detected 5 of 5 (100%) frontal, 9 of 11 (82%) sphenoidal, 14 of 19 (73%) ethmoidal, and 39 of 40 (97%) cases of maxillary sinusitis. The overall agreement was 88%. CONCLUSIONS: A single Waters view is an acceptable part of the initial evaluation of pediatric chronic sinusitis; however, a limited CT scan is a better alternative.

Chronic sinusitis among pediatric patients with chronic respiratory complaints.

We examined the prevalence of chronic sinusitis among children who presented to allergy clinics with chronic (> or = 3 months) respiratory symptoms. Ninety-one patients, ranging from 2 to 17 years of age with 62% male and 72% white, completed the study. Fifty-nine percent of patients had positive skin test results, and 25.3% had chronic asthma. Paranasal sinuses were examined by coronal sinus computed tomographic scan. Sixty-three percent (58 to 91) had chronic sinusitis, 5.5% (5 of 91) had concha bullosa, 1% (1 of 91) had foreign body, and 19% (19 of 91) had deviated nasal septums. Among symptoms of sneezing, nasal congestion, postnasal drip, coughing, wheezing, rhinorrhea, and headache, no single symptom was an acceptable predictor of abnormality on computed tomographic scan examinations. Combining the symptoms of moderate to severe rhinorrhea and cough with minimum sneezing had a specificity of 95% and a sensitivity of 38% in predicting the presence of chronic sinusitis. Allergic rhinitis (p = 0.27), mild deviated nasal septum (p = 0.11), unobstructive concha bullosa (p = 0.13), and passive exposure to cigarette smoke (p = 0.53) were not risk factors associated with sinus abnormalities. Age (r = 0.30, p = 0.004) in pediatric patients with chronic respiratory symptoms was the single risk factor significantly associated with abnormalities on sinus computed tomographic scan. Seventy-three percent of children 2 to 6 years of age, 74% of children 6 to 10 years of age, and 38% of children older than 10 had chronic sinusitis.(ABSTRACT TRUNCATED AT 250 WORDS)