Mapping of five subtype genes for muscarinic acetylcholine receptor to mouse chromosomes

Muscarinic acetylcholine receptors in mammals consist of five subtypes (M1-M5) encoded by distinct genes. They are widely expressed throughout the body and play a variety of roles in the peripheral and central nervous systems. Although their pharmacological properties have been studied extensively in vitro, colocalization of the multiple subtypes in each tissue and lack of subtype-specific ligands have hampered characterization of the respective subtypes in vivo. We have mapped mouse genomic loci for all five genes (Chrm1-5) by restriction fragment length variant (RFLV) analyses in interspecific backcross mice. Chrm1, Chrm2, and Chrm3 were mapped to chromosome (Chr) 19, 6, and 13, respectively. Both Chrm4 and Chrm5 were mapped to Chr 2. Although a comparison of their map positions with other mutations in their vicinities suggested a possibility that the El2 (epilepsy 2) allele might be a mutation in Chrm5, sequencing analyses of the Chrm5 gene in the El2 mutant mice did not support such a hypothesis.

Distribution of referred pain from the lumbar zygapophyseal joints and dorsal rami

OBJECTIVE

The purpose of this study was to determine the distribution of referred pain from the lumbar zygapophyseal joints (L1/2 to L5/S1) and the medial branches of the lumbar dorsal rami (Th12 to L5) in a large number of patients with chronic low back pain.

SETTING

This study was conducted at the pain clinics of Kanto Teishin Hospital and Hannan Central Hospital from March 1994 to May 1996.

PATIENTS AND DESIGN

Chronic low back pain patients who underwent zygapophyseal joint injection or radiofrequency facet denervation were studied. Under fluoroscopic control, the joints from L1/2 to L5/S1 were stimulated by injection of contrast medium, and the lumbar medial branches of the dorsal rami from Th12 to L5 underwent electrical stimulation during radiofrequency facet denervation.

OUTCOME MEASURES

If the injection or electrical stimulation reproduced the patient's usual pain, the distribution of induced pain was determined, and the sites of induced pain were divided into six areas.

RESULTS AND CONCLUSIONS

A total of 71 joints and 91 medial branches were studied in 48 patients. The distribution of referred pain from the L1/2 to L5/S1 zygapophyseal joints, and the medial branches of the dorsal rami from L1 to L5 were similar for each level stimulated, and the overlap of referred pain between each level was considerable.

Acute hydrocephalus in posterior fossa injury

This is the first known report of the use of computerized tomography (CT) scanning to examine acute hydrocephalus in posterior fossa injury. Of the 1802 patients with acute head trauma treated at Funabashi Municipal Medical Center, 53 (2.9%) had suffered injury to the posterior fossa. Of these, 12 patients (22.6%) had associated acute hydrocephalus: nine patients with acute epidural hematoma (AEH) and three with intracerebellar hematoma and contusion (IH/C). There was a significant relationship between cases of AEH with hydrocephalus and supratentorial extension, hematoma thickness of 15 mm or more, and abnormal mesencephalic cisterns. In cases of IH/C, bilateral lesions and no visible fourth ventricle were significant causes of hydrocephalus. According to these results, possible mechanisms of acute hydrocephalus in posterior fossa injury may be as follow: in cases of AEH, hematoma that extends to the supratentorial area compresses the aqueduct posteriorly and causes hydrocephalus; in cases of IH/C, hematoma and contusional lesions may directly occlude the fourth ventricle and cause acute hydrocephalus. Seven patients suffering from AEH with acute hydrocephalus underwent evacuation of their hematoma without external ventricular drainage. In these cases, CT scanning showed that the hydrocephalus improved immediately after evacuation of the hematoma. Two patients suffering from IH/C with hydrocephalus underwent a procedure for evacuation of the hematoma and external ventricular drainage. The authors do not believe that ventricular drainage is necessary in treating posterior fossa AEH. However, both evacuation of the hematoma and ventricular drainage are necessary in cases of IH/C with hydrocephalus to provide the patient with every chance for survival. There was no significant difference in mortality rates when cases of AEH with acute hydrocephalus (0%) were compared with cases of AEH without hydrocephalus (7.7%). The observed mortality rates in cases of IH/C with hydrocephalus and those without hydrocephalus were 100% and 15.4%, respectively; this is statistically significant.

[Trigeminal neuralgia caused by tortuous vertebrobasilar system--the clinical and imaging features]

Ten (6.8%) out of 146 patients with trigeminal neuralgia (TN) who underwent SPGR-MRI and 3D-TOF-MRA from August 1993 to October 1996, were found to have vascular compression caused by a tortuous vertebrobasilar system (TVBS). They were mostly males, demonstrated left-sided predominance, and had ipsilateral hemifacial spasm, compared with other 52 patients whose offending arteries were either superior cerebellar artery (SCA), anterior inferior cerebellar artery (AICA)or posterior inferior cerebellar artery (PICA). The patients who showed vascular compression by TVBS, presented an artery which compresses and dislocates the rootentry zone (REZ) of the trigeminal nerve, presses the brain stem at REZ and simultaneously compresses the REZ of the facial nerve. In addition, the diameters of the two branches of vertebrobasilar artery were not equal. These features indicate that the atherosclerotic change of the offending artery in TN caused by TVBS is more severe than that caused by SCA, AICA or PICA. This change causes an irregular running of artery which leads a strong compression of the trigeminal nerve REZ and of the brain stem. Consequently, the facial nerve REZ is severely affected leading to the presence of tic convulsif in TN caused by TVBS.

Angiographically unrecognized microaneurysms: intraoperative observation and operative technique

Twenty operated cases of angiographically unrecognized microaneurysm (AUM) have been analysed with special reference to intra-operative observations and clipping-technique. Among the patients with intracranial aneurysms that the authors' facility has operated upon, the incidence of asymptomatic incidental AUM that was 2 mm or smaller amounted to 3.7%. Thirteen cases of AUM were found on the middle cerebral artery; four AUMs arose from the M1 portion, four from the bifurcation, and five from the second bifurcation. Sixty percent of AUMs were recognized on the parent arteries of ruptured aneurysms. In 90% of cases the AUMs were broad based in shape and in 70% of cases exhibited a thin-walled neck and a thin-walled fundus. Intra-operative findings revealed four reasons why AUMs were not visible in the pre-operative angiograms: (1) the AUM was sandwiched between two arteries; (2) the AUM was completely hidden by a contiguous large or giant aneurysm; (3) the AUM was diagnosed by pre-operative angiogram as a bleb of the contiguous aneurysm; (4) the AUM was not visible on angiograms because the height of the AUM was extremely low. Twelve cases of AUM were successfully clipped using four different clipping techniques; (1) clipping parallel to the bifurcation in four, (2) clipping parallel to the parent artery in four, (3) pinch-clipping in two of the cases, and (4) cross clipping in two of the cases. The other eight cases were wrapped and coated. AUMs may be present during the direct operation of intracranial aneurysms and in intravascular surgery. Neurosurgeons and neuroradiologists need to explain the possible existence of AUMs to patients and their families.

[Identification of offending vessels in trigeminal neuralgia and hemifacial spasm using SPGR-MRI and 3D-TOF-MRA]

We investigated 100 consecutive patients with trigeminal neuralgia (TN) and 53 patients with hemifacial spasm (HFS) concerning the anatomical relationship between the root entry (exit) zone (REZ) of cranial nerve and the offending artery, using spoiled GRASS MRI (SPGR-MRI) and three dimensional-time of fly-MRA (MRA). In 67 of 100 (67%) patiets with TN, this new radiological method, SPGR-MRI and MRA demonstrated the relationship between the fifth cranial nerve root and offending artery causing neurovascular compression (NVC), and in 46 of 53 (87%) with HFS, demonstrated the similar relationship between seventh and eighth nerve complex and offending artery. Microvascular decompression (MVD) was performed in 10 with HFS, and NVC of the REZ of the facial nerve caused by the offending artery was exactly predicted by SPGR-MRI and MRA in 9 (90%). The combination of SPGR-MRI and MRA is very useful for demonstrating NVC as the cause of TN and HFS. On the other hand, we investigated asymptomatic 206 trigeminal and 253 facial nerves about the relationship between their REZ and the surrounding structures using the similar method. The contact of REZ of cranial nerve with surrounding artery is demonstrated in 31.6% of trigeminal nerves and in 22.5% of facial nerves. These results indicate that the contact of REZ of cranial nerve with surrounding artery is not rare in healthy subjects, though causing TN and HFS in particular patients. In this context, we discussed the difference between the contact which is asymptomatic and the compression which is symptomatic.

Development and evaluation of oral reporting system for PACS

Experimental workstations for oral reporting and synchronized image filing have been developed and evaluated by radiologists and referring physicians. The file media is a 5.25-inch rewritable magneto-optical disk of 600-Mb capacity whose file format is in accordance with the IS&C specification. The results of evaluation tell that this system is superior to other existing methods of the same kind such as transcribing, dictating, handwriting, typewriting and key selections. The most significant advantage of the system is that images and their interpretation are never separated. The first practical application to the teaching file and the teaching conference is contemplated in the Osaka University Hospital. This system is a complete digital system in terms of images, voices and demographic data, so that on-line transmission, off-line communication or filing to any database will be easily realized in a PACS environment. We are developing an integrated system of a speech recognizer connected to this digitized oral system.

[Development of oral reporting system in PACS environment]

An experimental radiologic reporting system using oral presentations has been developed and tested. The rewritable and compact magneto-optical disk (MOD) is employed to store oral diagnostic reports together with read radiologic images. The MOD is 5.25 inches in diameter, has a 600 MB memory capacity, and is erasable, light and compact. Advantages of the system are simultaneous retrieval of oral reports by a radiologist and the images he or she interpreted, and the capability of media circulation in addition to the function of filing. Thus MOD has a multimedia function of both off-line communication and filing. When medical images are interpreted and oral presentations are registered, automatically digitized oral reports and digitized images are filed in the MOD. Referring physicians can get oral diagnostic reports and can see the images at the same time on a personal computer. Furthermore, integration with voice recognition capability is being tried in our experiment.

[Treatment of cancer pain with the percutaneous electrocoagulation of spinal nerves]

To our knowledge, this is the first report of high-frequency thermocoagulation applied to the spinal root. We treated 34 patients suffering from cancer pain with this technique. Among these patients, cancer pain occurred due to intrapelvic metastasis in 11 patients, and 13 complained of chest pain due to cancer. Every patient was considered to have good or excellent response when his or her pain score was reduced to 6 points or less from the score before thermocoagulation; 10 points. Based on this criterion, 54.5% and 30.8% of the above-mentioned patients showed good and excellent responses respectively one month after treatment. This technique, therefore, was considered to be effective with less side effects compared with other nerve blocking techniques.

[Six cases of epidural abscess probably caused by epidural block and examination by gadolinium-MRI imaging]

We treated six cases of epidural abscess caused probably by epidural block. Three patients were given only chemotherapy and the other three underwent surgical treatment. Four patients were cured completely, but bilateral paresis in the lower limbs persisted in two patients. The symptoms at onset, laboratory findings, imaging findings including MRI and CT, treatment methods and prognosis were reported. Accelerated blood sedimentation rate, positive CRP results and abnormal findings at the site of the catheter insertion appeared to be important initial signs for the early discovery of epidural abscesses. The route of infection, selection of treatment methods, methods of prevention and examination by Gadolinium-MRI imaging were also discussed.

[Thoracic and lumbar sympathetic ganglion block for post herpetic neuralgia]

Of 2,667 patients with herpes zoster who visited our hospital between January 1972 and March 1989, 136 patients whose treatments were started after more than 6 months following the onset were subjects of the present study. Thus we performed a retrospective study of the therapeutic effects of sympathetic ganglion block (using alcohol) on postherpetic neuralgia left untreated for more than 6 months after the onset. After more than 1 year following the onset, the disease was nearly or completely cured in 9 of 37 patients (24%) treated with sympathetic ganglion block with alcohol and in 6 of 34 (17.6%) without the treatment. Thus the patients who underwent sympathetic ganglion block with alcohol tended to show better results. The above findings suggest that, in patients with postherpetic neuralgia in whom the initiation of treatment was delayed, treatment mainly consisting of thoracic or lumbar sympathetic ganglion block using alcohol in combination with antidepressants and antianxiety drugs can greatly improve patients' activities of daily life and that, at present, this method is most effective in relieving postherpetic neuralgia.

[Endoscopic stage classification of peptic ulcer and characterization of the healing process by proton pump inhibitors]

Proton pump inhibitors are highly effective for gastric acid secretion and have been shown to be superior to histamine H2-receptor antagonists. The superiority of proton pump inhibitors over H2-receptor antagonists was more pronounced in duodenal ulcers. Omeprazole reduced the time required by H2-receptor antagonists the healing of duodenal ulcers by 2/3 to 1/2. On the other hand, unusual endoscopic findings, such as shallow white coat or protrusion of the ulcer floor, were noted in the healing stage of gastric ulcers with H2-receptor antagonists. Whereas these findings were rarely seen with conventional drugs. Histologically, the protrusion was made up granulation tissue consisting of cell infiltration and renewed capillaries with or without regenerated epithelia. These unusual endoscopic findings may be observed in the peptic ulcers treated with proton pump inhibitors.

Effect of pirenzepine on aminopyrine uptake by isolated guinea pig parietal cells

The inhibitory action of pirenzepine on acid secretion of isolated guinea pig parietal cells was investigated by the aminopyrine method. Pirenzepine markedly inhibited acid secretion of isolated parietal cells induced by carbachol in a dose-dependent manner but showed no inhibition on acid secretion stimulated by histamine. These results may suggest a direct action of pirenzepine on muscarinic receptors in parietal cells.

[Palinopsia caused by tentorial meningioma. Case report]

Palinopsia is defined as persistence or recurrence of a visual image when the stimulus is no longer present. The authors describe a female patient with a left tentorial meningioma who experienced recurrent visual images. Computed tomography revealed a well demarcated, high-density mass above the left side of the tentorium, but formal field testing revealed no visual field defect. The findings in this case suggest that the palinopsia may have been the result of disordered temporal synthesis of visual experiences.

[The administration of continuous epidural block under prone position with fluoroscopic guidance]

Continuous epidural block is often used for the treatment of pain. But there have been unsuccessful cases by the routine blind method. We devised a modified method of administering continuous epidural block under prone position with fluoroscopic guidance. The purpose of this study was to evaluate the utility of our modified method. There were 18 cases with pain of lumbar region and 28 cases of thoracocervical region in whom it was not possible to obtain successful control of pain by routine method. By our method, 14 cases (77.8%) with pain of lumbar region and 24 cases (85.7%) of thoracocervical region had effective epidural catheterization. There was no complication. As unsuccessful cases were accompanied with epidural adhesion or psychological disease, they might have no indication for continuous epidural block.

The effect of omeprazole on ultrastructural changes in gastric parietal cells

This study was designed to compare the effects of omeprazole and cimetidine on ultrastructural changes in parietal cells of guinea pigs during histamine stimulation. Both omeprazole and cimetidine remarkably inhibited acid secretion induced by histamine stimulation. Omeprazole, however, failed to prevent the morphological transition of parietal cells to an active stage during histamine stimulation, in contrast to cimetidine which inhibited the morphological transition. In addition, it was noticed that administration of omeprazole caused vacuolation in approximately 27% of all parietal cells. This phenomenon was not seen in control animals with histamine stimulation alone and only very rarely in cimetidine treated animals. Ultrastructural findings suggested that vacuoles originated in secretory canaliculi of parietal cells. These results may be the key to explain the difference of the inhibitory mechanism between omeprazole which acts on the final step of intracellular process (so-called proton pump) and cimetidine which acts on the H2-receptor site of plasma membrane.

Chronic subdural hematomas. Time-density curve and iodine concentration in enhanced CT

Surgery was undertaken on 32 chronic subdural hematomas in a series of 28 patients who had preoperatively undergone delayed contrast-enhanced computed tomography (DCECT). Time-density curves on DCECT and iodine concentrations of subdural specimens revealed that chronic subdural hematomas, regardless of density, were significantly enhanced by the entrance of intravascular contrast medium into the interior of hematomas. The ingress of intravascular contrast medium into the interior of the hematomas was chemically proven and might result from a complex transcapillary shift.

Isolation of parietal cells from guinea-pig gastric mucosa by a Percoll density gradient

Isolation of parietal cells from guinea-pig gastric mucosa was performed by density gradient centrifugation using percoll, a new gradient medium composed of colloidal silica coated with polyvinylpyrolidone. The gastric mucosa of the oxyntic gland area was exfoliated, minced and digested with 2.0 mg/ml of dispase and 0.1 mg/ml of collagenase. Dispersed mucosal cells were applied to the percoll density gradient. Parietal cells were fractionated in the layer between 1.04 and 1.06 g/ml in density with purity 80 approximately 90%. For identification of parietal cells staining with tetranitrobluetetrazolium and electron microscopy were used in addition to common staining. The viability of the cells was over 95% assessed by trypan-blue exclusion. The parietal cells obtained responded actively to histamine stimulation when 14C-aminopyrine uptake was used as an functional index. In conclusion, percoll density gradient medium is suitable for yielding isolated parietal cells with both high purity and high viability.