Increased number of substitutions in the D-loop of mitochondrial DNA in the sudden infant death syndrome

The purpose of the present study was to investigate substitutions in the D-loop of mitochondrial DNA (mtDNA) in sudden infant death syndrome (SIDS) and controls, since several observations indicate the involvement of mtDNA mutations in SIDS. These include elevated levels of vitreous humour hypoxanthine in SIDS victims, familial clustering without mendelian traits, and observations of increased sleepiness and a lower activity score in infants who later succumbed to SIDS. Eighty-two cases of SIDS and 133 controls were investigated and the D-loop sequences were recorded in the base-pair range 16 055-16 500 in the mtDNA sequence. The sequencing was carried out using the Applied Biosystems Sequenase dye terminator method and a ABD373A sequencer. The recorded D-loop sequences were compared with the Cambridge sequence and differences were recorded as substitutions. The SIDS cases had a tendency towards a higher substitution rate in the D-loop than the controls ( p = 0.088). This observation makes it interesting to search for deleterious mutations in other locations in the mtDNA.     

Further observations upon gastric function in rats after prolonged administration of an anticholinergic drug,propantheline bromide

Gastric function was assessed in Wistar rats which received propantheline bromide by daily injection for 20 weeks. The results were compared with those from two control groups, one of which was injected daily with saline for 20 weeks. Gastric acid secretion, as measured by test meal and after ligation of the pylorus, was similar in all three groups. Acid secretion, as measured by test meal with pentagastrin 100 µg/kg body weight, gastric emptying, and fundic mucosal volume, expressed in terms of body weight, were all significantly increased in rats given propantheline. Only those measurements of acid secretion obtained by test meal with pentagastrin showed a significant correlation with fundic mucosal volume. Hence, since this method provides the most accurate indication of secretory capacity, it is concluded that the prolonged parenteral administration of propantheline may lead to an increase in parietal cell mass and its correlate, maximal secretory capacity. The mechanism by which these changes are produced is obscure.The author is grateful to Mr. Howard Ireson for his expert technical assistance, and to Mr. Ralph Marshall, Department of Medical Illustration, Cardiff Royal Infirmary, for the photography employed.Propantheline bromide (Pro-Banthine) was generously supplied by G. D. Searle and Co., Ltd.     

Is this bone infected or not? Differentiating neuro-osteoarthropathy from osteomyelitis in the diabetic foot

Osteomyelitis (bone infection) and neuro-osteoarthropathy (Charcot arthropathy) are limb-threatening complications of diabetic neuropathy with very different therapies. Distinguishing between them may be difficult, but it is important. In Charcot arthropathy, noninfectious soft tissue inflammation accompanies rapidly progressive destruction, first of joints, then of bone. This occurs in a well-vascularized and severely neuropathic, but nonulcerated, foot. In osteomyelitis, chronic soft tissue ulceration precedes infection of bone, which may be physically exposed. Magnetic resonance imaging and bone biopsy are the preferred diagnostic tests, provided adequate technical and interpretive skills are available.     

Effect of luminal acidification on guinea pig gastric mucosa

H⁺ secretion was studied in guinea pig fundic mucosa incubated in (A) bicarbonate-Ringer's gassed with 95% O₂-5% CO₂, or (B) HEPES gassed with 100% O₂ before and after luminal pH was lowered to 2.0 for periods up to 90 min. At pH 2.0 for 60 min, H⁺ secretion in group A tissues fell by 35±4% (P=0.02) from a control rate of 1.35±0.09 eq/cm²/hr and in group B tissues by 50±11% (P=0.01) from a control rate of 1.59±0.08 eq/cm²/hr. After 90 min at pH 2.0, H⁺ secretion in group A fell by 53±8% (P=0.02) from a control rate of 1.47±0.07 eq/cm²/hr and in group B fell by 44±6% (P=0.01) from a control rate of 1.38±0.07 eq/cm²/hr. Histamine 1×10^–4 M stimulation following exposure to pH 2.0 for 90 min increased secretion in group A tissues from 0.80 ±0.14 to 1.06±0.13 eq/cm²/hr (P<0.05), compared with an increase in nonacidified controls from 1.15±0.22 to 1.80±0.20 eq/cm²/hr (P<0.05) and in group B tissues from 1.27±0.10 to 1.56±0.19 eq/cm²/hr (P<0.05) compared with nonacidified controls from 1.43±0.22 to 2.23±0.41 eq/cm²/hr (P<0.05). Secretory function and electrical characteristics were adversely affected by luminal acidification to pH 2.0 and suggested a breach in the mucosal barrier with damage to parietal cells.This study was funded by the National Institute of Health Grant No. AM 15681.